From b4455bbfd65b74fa12927e83794d72966a4ee5bb Mon Sep 17 00:00:00 2001
From: Yan Zhang <2351748+Eskibear@users.noreply.github.com>
Date: Wed, 8 Nov 2023 12:27:33 +0800
Subject: [PATCH 1/8] forbid wildcard in label filters (#22)

---
 package-lock.json                   | 51 ++++++++++++++---
 package.json                        |  3 +-
 src/AzureAppConfigurationImpl.ts    | 25 ++++++++-
 src/AzureAppConfigurationOptions.ts | 21 ++++++-
 test/load.test.js                   | 87 ++++++++++++++++-------------
 test/utils/testHelper.js            | 31 ++++++++--
 6 files changed, 165 insertions(+), 53 deletions(-)

diff --git a/package-lock.json b/package-lock.json
index 71d02854..ada9f0d9 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -29,7 +29,8 @@
         "rollup-plugin-dts": "^5.3.0",
         "sinon": "^15.2.0",
         "tslib": "^2.6.0",
-        "typescript": "^5.1.6"
+        "typescript": "^5.1.6",
+        "uuid": "^9.0.1"
       }
     },
     "node_modules/@aashutoshrathi/word-wrap": {
@@ -208,6 +209,14 @@
         "node": ">=14.0.0"
       }
     },
+    "node_modules/@azure/identity/node_modules/uuid": {
+      "version": "8.3.2",
+      "resolved": "https://registry.npmjs.org/uuid/-/uuid-8.3.2.tgz",
+      "integrity": "sha512-+NYs2QeMWy+GWFOEm9xnn6HCDp0l7QBD7ml8zLUmJ+93Q5NF0NocErnwkTkXVFNiX3/fpC6afS8Dhb/gz7R7eg==",
+      "bin": {
+        "uuid": "dist/bin/uuid"
+      }
+    },
     "node_modules/@azure/keyvault-secrets": {
       "version": "4.7.0",
       "resolved": "https://registry.npmjs.org/@azure/keyvault-secrets/-/keyvault-secrets-4.7.0.tgz",
@@ -272,6 +281,14 @@
         "node": "10 || 12 || 14 || 16 || 18"
       }
     },
+    "node_modules/@azure/msal-node/node_modules/uuid": {
+      "version": "8.3.2",
+      "resolved": "https://registry.npmjs.org/uuid/-/uuid-8.3.2.tgz",
+      "integrity": "sha512-+NYs2QeMWy+GWFOEm9xnn6HCDp0l7QBD7ml8zLUmJ+93Q5NF0NocErnwkTkXVFNiX3/fpC6afS8Dhb/gz7R7eg==",
+      "bin": {
+        "uuid": "dist/bin/uuid"
+      }
+    },
     "node_modules/@babel/code-frame": {
       "version": "7.22.13",
       "resolved": "https://registry.npmjs.org/@babel/code-frame/-/code-frame-7.22.13.tgz",
@@ -3379,9 +3396,14 @@
       }
     },
     "node_modules/uuid": {
-      "version": "8.3.2",
-      "resolved": "https://registry.npmjs.org/uuid/-/uuid-8.3.2.tgz",
-      "integrity": "sha512-+NYs2QeMWy+GWFOEm9xnn6HCDp0l7QBD7ml8zLUmJ+93Q5NF0NocErnwkTkXVFNiX3/fpC6afS8Dhb/gz7R7eg==",
+      "version": "9.0.1",
+      "resolved": "https://registry.npmjs.org/uuid/-/uuid-9.0.1.tgz",
+      "integrity": "sha512-b+1eJOlsR9K8HJpow9Ok3fiWOWSIcIzXodvv0rQjVoOVNpWMpxf1wZNpt4y9h10odCNrqnYp1OBzRktckBe3sA==",
+      "dev": true,
+      "funding": [
+        "https://github.com/sponsors/broofa",
+        "https://github.com/sponsors/ctavan"
+      ],
       "bin": {
         "uuid": "dist/bin/uuid"
       }
@@ -3656,6 +3678,13 @@
         "stoppable": "^1.1.0",
         "tslib": "^2.2.0",
         "uuid": "^8.3.0"
+      },
+      "dependencies": {
+        "uuid": {
+          "version": "8.3.2",
+          "resolved": "https://registry.npmjs.org/uuid/-/uuid-8.3.2.tgz",
+          "integrity": "sha512-+NYs2QeMWy+GWFOEm9xnn6HCDp0l7QBD7ml8zLUmJ+93Q5NF0NocErnwkTkXVFNiX3/fpC6afS8Dhb/gz7R7eg=="
+        }
       }
     },
     "@azure/keyvault-secrets": {
@@ -3705,6 +3734,13 @@
         "@azure/msal-common": "13.3.0",
         "jsonwebtoken": "^9.0.0",
         "uuid": "^8.3.0"
+      },
+      "dependencies": {
+        "uuid": {
+          "version": "8.3.2",
+          "resolved": "https://registry.npmjs.org/uuid/-/uuid-8.3.2.tgz",
+          "integrity": "sha512-+NYs2QeMWy+GWFOEm9xnn6HCDp0l7QBD7ml8zLUmJ+93Q5NF0NocErnwkTkXVFNiX3/fpC6afS8Dhb/gz7R7eg=="
+        }
       }
     },
     "@babel/code-frame": {
@@ -5947,9 +5983,10 @@
       }
     },
     "uuid": {
-      "version": "8.3.2",
-      "resolved": "https://registry.npmjs.org/uuid/-/uuid-8.3.2.tgz",
-      "integrity": "sha512-+NYs2QeMWy+GWFOEm9xnn6HCDp0l7QBD7ml8zLUmJ+93Q5NF0NocErnwkTkXVFNiX3/fpC6afS8Dhb/gz7R7eg=="
+      "version": "9.0.1",
+      "resolved": "https://registry.npmjs.org/uuid/-/uuid-9.0.1.tgz",
+      "integrity": "sha512-b+1eJOlsR9K8HJpow9Ok3fiWOWSIcIzXodvv0rQjVoOVNpWMpxf1wZNpt4y9h10odCNrqnYp1OBzRktckBe3sA==",
+      "dev": true
     },
     "which": {
       "version": "2.0.2",
diff --git a/package.json b/package.json
index 148f1718..b354ca12 100644
--- a/package.json
+++ b/package.json
@@ -47,7 +47,8 @@
     "rollup-plugin-dts": "^5.3.0",
     "sinon": "^15.2.0",
     "tslib": "^2.6.0",
-    "typescript": "^5.1.6"
+    "typescript": "^5.1.6",
+    "uuid": "^9.0.1"
   },
   "dependencies": {
     "@azure/app-configuration": "^1.4.1",
diff --git a/src/AzureAppConfigurationImpl.ts b/src/AzureAppConfigurationImpl.ts
index 323ac2a8..faaf2524 100644
--- a/src/AzureAppConfigurationImpl.ts
+++ b/src/AzureAppConfigurationImpl.ts
@@ -44,7 +44,10 @@ export class AzureAppConfigurationImpl extends Map<string, unknown> implements A
 
     public async load() {
         const keyValues: [key: string, value: unknown][] = [];
-        const selectors = this.options?.selectors ?? [{ keyFilter: KeyFilter.Any, labelFilter: LabelFilter.Null }];
+
+        // validate selectors
+        const selectors = getValidSelectors(this.options?.selectors);
+
         for (const selector of selectors) {
             const listOptions: ListConfigurationSettingsOptions = {
                 keyFilter: selector.keyFilter,
@@ -105,3 +108,23 @@ export class AzureAppConfigurationImpl extends Map<string, unknown> implements A
         return headers;
     }
 }
+
+function getValidSelectors(selectors?: { keyFilter: string, labelFilter?: string }[]) {
+    if (!selectors || selectors.length === 0) {
+        // Default selector: key: *, label: \0
+        return [{ keyFilter: KeyFilter.Any, labelFilter: LabelFilter.Null }];
+    }
+    return selectors.map(selectorCandidate => {
+        const selector = { ...selectorCandidate };
+        if (!selector.keyFilter) {
+            throw new Error("Key filter cannot be null or empty.");
+        }
+        if (!selector.labelFilter) {
+            selector.labelFilter = LabelFilter.Null;
+        }
+        if (selector.labelFilter.includes("*") || selector.labelFilter.includes(",")) {
+            throw new Error("The characters '*' and ',' are not supported in label filters.");
+        }
+        return selector;
+    });
+}
\ No newline at end of file
diff --git a/src/AzureAppConfigurationOptions.ts b/src/AzureAppConfigurationOptions.ts
index 975cb838..11a9ba5b 100644
--- a/src/AzureAppConfigurationOptions.ts
+++ b/src/AzureAppConfigurationOptions.ts
@@ -8,7 +8,26 @@ export const MaxRetries = 2;
 export const MaxRetryDelayInMs = 60000;
 
 export interface AzureAppConfigurationOptions {
-    selectors?: { keyFilter: string, labelFilter: string }[];
+    /**
+     * Specify what key-values to include in the configuration provider.  include multiple sets of key-values
+     *
+     * @property keyFilter:
+     * The key filter to apply when querying Azure App Configuration for key-values.
+     * An asterisk `*` can be added to the end to return all key-values whose key begins with the key filter.
+     * e.g. key filter `abc*` returns all key-values whose key starts with `abc`.
+     * A comma `,` can be used to select multiple key-values. Comma separated filters must exactly match a key to select it.
+     * Using asterisk to select key-values that begin with a key filter while simultaneously using comma separated key filters is not supported.
+     * E.g. the key filter `abc*,def` is not supported. The key filters `abc*` and `abc,def` are supported.
+     * For all other cases the characters: asterisk `*`, comma `,`, and backslash `\` are reserved. Reserved characters must be escaped using a backslash (\).
+     * e.g. the key filter `a\\b\,\*c*` returns all key-values whose key starts with `a\b,*c`.
+     *
+     * @property labelFilter:
+     * The label filter to apply when querying Azure App Configuration for key-values.
+     * By default, the "null label" will be used, matching key-values without a label.
+     * The characters asterisk `*` and comma `,` are not supported.
+     * Backslash `\` character is reserved and must be escaped using another backslash `\`.
+     */
+    selectors?: { keyFilter: string, labelFilter?: string }[];
     trimKeyPrefixes?: string[];
     clientOptions?: AppConfigurationClientOptions;
     keyVaultOptions?: AzureAppConfigurationKeyVaultOptions;
diff --git a/test/load.test.js b/test/load.test.js
index 5a8682a9..36d9d8bf 100644
--- a/test/load.test.js
+++ b/test/load.test.js
@@ -12,54 +12,30 @@ const {
     createMockedConnectionString,
     createMockedEnpoint,
     createMockedTokenCredential,
+    createMockedKeyValue,
 } = require("./utils/testHelper");
 
 const mockedKVs = [{
-    value: "red",
     key: "app.settings.fontColor",
-    label: null,
-    contentType: "",
-    lastModified: "2023-05-04T04:34:24.000Z",
-    tags: {},
-    etag: "210fjkPIWZMjFTi_qyEEmmsJjtUjj0YQl-Y3s1m6GLw",
-    isReadOnly: false
+    value: "red",
 }, {
-    value: "40",
     key: "app.settings.fontSize",
-    label: null,
-    contentType: "",
-    lastModified: "2023-05-04T04:32:56.000Z",
-    tags: {},
-    etag: "GdmsLWq3mFjFodVEXUYRmvFr3l_qRiKAW_KdpFbxZKk",
-    isReadOnly: false
+    value: "40",
 }, {
-    value: "TestValue",
     key: "TestKey",
     label: "Test",
-    contentType: "",
-    lastModified: "2023-05-04T04:32:56.000Z",
-    tags: {},
-    etag: "GdmsLWq3mFjFodVEXUYRmvFr3l_qRiKAW_KdpFbxZKk",
-    isReadOnly: false
+    value: "TestValue",
+}, {
+    key: "TestKey",
+    label: "Prod",
+    value: "TestValueForProd",
 }, {
-    value: null,
     key: "KeyForNullValue",
-    label: "",
-    contentType: "",
-    lastModified: "2023-05-04T04:32:56.000Z",
-    tags: {},
-    etag: "GdmsLWq3mFjFodVEXUYRmvFr3l_qRiKAW_KdpFbxZKk",
-    isReadOnly: false
+    value: null,
 }, {
-    value: "",
     key: "KeyForEmptyValue",
-    label: "",
-    contentType: "",
-    lastModified: "2023-05-04T04:32:56.000Z",
-    tags: {},
-    etag: "GdmsLWq3mFjFodVEXUYRmvFr3l_qRiKAW_KdpFbxZKk",
-    isReadOnly: false
-}];
+    value: "",
+}].map(createMockedKeyValue);
 
 describe("load", function () {
     before(() => {
@@ -118,8 +94,7 @@ describe("load", function () {
         expect(settings.get("fontColor")).eq("red");
         expect(settings.has("fontSize")).eq(true);
         expect(settings.get("fontSize")).eq("40");
-        expect(settings.has("TestKey")).eq(true);
-        expect(settings.get("TestKey")).eq("TestValue");
+        expect(settings.has("TestKey")).eq(false);
     });
 
     it("should trim longest key prefix first", async () => {
@@ -136,8 +111,7 @@ describe("load", function () {
         expect(settings.get("fontColor")).eq("red");
         expect(settings.has("fontSize")).eq(true);
         expect(settings.get("fontSize")).eq("40");
-        expect(settings.has("Key")).eq(true);
-        expect(settings.get("Key")).eq("TestValue");
+        expect(settings.has("TestKey")).eq(false);
     });
 
     it("should support null/empty value", async () => {
@@ -149,4 +123,39 @@ describe("load", function () {
         expect(settings.has("KeyForEmptyValue")).eq(true);
         expect(settings.get("KeyForEmptyValue")).eq("");
     });
+
+    it("should not support * or , in label filters", async () => {
+        const connectionString = createMockedConnectionString();
+        const loadWithWildcardLabelFilter = load(connectionString, {
+            selectors: [{
+                keyFilter: "app.*",
+                labelFilter: "*"
+            }]
+        });
+        expect(loadWithWildcardLabelFilter).to.eventually.rejected;
+
+        const loadWithMultipleLabelFilter = load(connectionString, {
+            selectors: [{
+                keyFilter: "app.*",
+                labelFilter: "labelA,labelB"
+            }]
+        });
+        expect(loadWithMultipleLabelFilter).to.eventually.rejected;
+    });
+
+    it("should override config settings with same key but different label", async () => {
+        const connectionString = createMockedConnectionString();
+        const settings = await load(connectionString, {
+            selectors: [{
+                keyFilter: "Test*",
+                labelFilter: "Test"
+            }, {
+                keyFilter: "Test*",
+                labelFilter: "Prod"
+            }]
+        });
+        expect(settings).not.undefined;
+        expect(settings.has("TestKey")).eq(true);
+        expect(settings.get("TestKey")).eq("TestValueForProd");
+    });
 })
diff --git a/test/utils/testHelper.js b/test/utils/testHelper.js
index 11e43f71..b58aa859 100644
--- a/test/utils/testHelper.js
+++ b/test/utils/testHelper.js
@@ -5,16 +5,27 @@ const sinon = require("sinon");
 const { AppConfigurationClient } = require("@azure/app-configuration");
 const { ClientSecretCredential } = require("@azure/identity");
 const { SecretClient } = require("@azure/keyvault-secrets");
+const uuid = require("uuid");
 
 const TEST_CLIENT_ID = "62e76eb5-218e-4f90-8261-000000000000";
 const TEST_TENANT_ID = "72f988bf-86f1-41af-91ab-000000000000";
 const TEST_CLIENT_SECRET = "Q158Q~2JtUwVbuq0Mzm9ocH2umTB000000000000";
 
 function mockAppConfigurationClientListConfigurationSettings(kvList) {
-    function* testKvSetGnerator() {
-        yield* kvList;
+    function* testKvSetGnerator(kvs) {
+        yield* kvs;
     }
-    sinon.stub(AppConfigurationClient.prototype, "listConfigurationSettings").callsFake(() => testKvSetGnerator());
+    sinon.stub(AppConfigurationClient.prototype, "listConfigurationSettings").callsFake((listOptions) => {
+        const keyFilter = listOptions.keyFilter ?? "*";
+        const labelFilter = listOptions.labelFilter ?? "*";
+        const kvs = kvList.filter(kv => {
+            const keyMatched = keyFilter.endsWith("*") ? kv.key.startsWith(keyFilter.slice(0, keyFilter.length - 1)) : kv.key === keyFilter;
+            const labelMatched = labelFilter.endsWith("*") ? kv.label.startsWith(labelFilter.slice(0, labelFilter.length - 1))
+                : (labelFilter === "\0" ? kv.label === null : kv.label === labelFilter); // '\0' in labelFilter, null in config setting.
+            return keyMatched && labelMatched;
+        })
+        return testKvSetGnerator(kvs);
+    });
 }
 
 // uriValueList: [["<secretUri>", "value"], ...]
@@ -74,6 +85,17 @@ const createMockedJsonKeyValue = (key, value) => ({
     isReadOnly: false
 });
 
+const createMockedKeyValue = (props) => (Object.assign({
+    value: "TestValue",
+    key: "TestKey",
+    label: null,
+    contentType: "",
+    lastModified: new Date().toISOString(),
+    tags: {},
+    etag: uuid.v4(),
+    isReadOnly: false
+}, props));
+
 module.exports = {
     sinon,
     mockAppConfigurationClientListConfigurationSettings,
@@ -84,5 +106,6 @@ module.exports = {
     createMockedConnectionString,
     createMockedTokenCredential,
     createMockedKeyVaultReference,
-    createMockedJsonKeyValue
+    createMockedJsonKeyValue,
+    createMockedKeyValue
 }
\ No newline at end of file

From 5f35f2d5b96d43769e859d1b9e24955217e101f8 Mon Sep 17 00:00:00 2001
From: Yan Zhang <2351748+Eskibear@users.noreply.github.com>
Date: Thu, 9 Nov 2023 04:59:46 +0800
Subject: [PATCH 2/8] Rewrite test cases in TS (#24)

---
 .eslintrc                                     |  3 +-
 .gitignore                                    |  3 +-
 package-lock.json                             | 57 +++++++++++++++++++
 package.json                                  | 12 ++--
 src/AzureAppConfiguration.ts                  |  2 +-
 test/.eslintrc                                |  5 --
 ...tOptions.test.js => clientOptions.test.ts} | 15 +++--
 test/exportedApi.ts                           |  4 ++
 test/{json.test.js => json.test.ts}           | 14 ++---
 test/{keyvault.test.js => keyvault.test.ts}   | 17 +++---
 test/{load.test.js => load.test.ts}           | 15 ++---
 ...Tracing.test.js => requestTracing.test.ts} | 19 ++++---
 test/utils/{testHelper.js => testHelper.ts}   | 43 +++++++-------
 tsconfig.base.json                            | 24 ++++++++
 tsconfig.json                                 | 17 +-----
 tsconfig.test.json                            | 10 ++++
 16 files changed, 167 insertions(+), 93 deletions(-)
 delete mode 100644 test/.eslintrc
 rename test/{clientOptions.test.js => clientOptions.test.ts} (86%)
 create mode 100644 test/exportedApi.ts
 rename test/{json.test.js => json.test.ts} (90%)
 rename test/{keyvault.test.js => keyvault.test.ts} (84%)
 rename test/{load.test.js => load.test.ts} (91%)
 rename test/{requestTracing.test.js => requestTracing.test.ts} (86%)
 rename test/utils/{testHelper.js => testHelper.ts} (68%)
 create mode 100644 tsconfig.base.json
 create mode 100644 tsconfig.test.json

diff --git a/.eslintrc b/.eslintrc
index 754a9f38..8b96047e 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -40,5 +40,6 @@
                 "avoidEscape": true
             }
         ],
-    },
+        "@typescript-eslint/no-explicit-any": "off"
+    }
 }
\ No newline at end of file
diff --git a/.gitignore b/.gitignore
index d946d028..1ccd7b97 100644
--- a/.gitignore
+++ b/.gitignore
@@ -400,6 +400,7 @@ FodyWeavers.xsd
 # bundled folder
 dist/
 dist-esm/
+out/
 types/
 
 # dotenv
@@ -409,4 +410,4 @@ types/
 *.tgz
 
 # examples
-examples/package-lock.json
\ No newline at end of file
+examples/package-lock.json
diff --git a/package-lock.json b/package-lock.json
index ada9f0d9..9987ca56 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -15,7 +15,10 @@
       },
       "devDependencies": {
         "@rollup/plugin-typescript": "^11.1.2",
+        "@types/mocha": "^10.0.4",
         "@types/node": "^20.5.7",
+        "@types/sinon": "^17.0.1",
+        "@types/uuid": "^9.0.7",
         "@typescript-eslint/eslint-plugin": "^6.6.0",
         "@typescript-eslint/parser": "^6.6.0",
         "chai": "^4.3.7",
@@ -832,6 +835,12 @@
       "integrity": "sha512-U3PUjAudAdJBeC2pgN8uTIKgxrb4nlDF3SF0++EldXQvQBGkpFZMSnwQiIoDU77tv45VgNkl/L4ouD+rEomujw==",
       "dev": true
     },
+    "node_modules/@types/mocha": {
+      "version": "10.0.4",
+      "resolved": "https://registry.npmjs.org/@types/mocha/-/mocha-10.0.4.tgz",
+      "integrity": "sha512-xKU7bUjiFTIttpWaIZ9qvgg+22O1nmbA+HRxdlR+u6TWsGfmFdXrheJoK4fFxrHNVIOBDvDNKZG+LYBpMHpX3w==",
+      "dev": true
+    },
     "node_modules/@types/node": {
       "version": "20.8.7",
       "resolved": "https://registry.npmjs.org/@types/node/-/node-20.8.7.tgz",
@@ -847,6 +856,27 @@
       "integrity": "sha512-MMzuxN3GdFwskAnb6fz0orFvhfqi752yjaXylr0Rp4oDg5H0Zn1IuyRhDVvYOwAXoJirx2xuS16I3WjxnAIHiQ==",
       "dev": true
     },
+    "node_modules/@types/sinon": {
+      "version": "17.0.1",
+      "resolved": "https://registry.npmjs.org/@types/sinon/-/sinon-17.0.1.tgz",
+      "integrity": "sha512-Q2Go6TJetYn5Za1+RJA1Aik61Oa2FS8SuJ0juIqUuJ5dZR4wvhKfmSdIqWtQ3P6gljKWjW0/R7FZkA4oXVL6OA==",
+      "dev": true,
+      "dependencies": {
+        "@types/sinonjs__fake-timers": "*"
+      }
+    },
+    "node_modules/@types/sinonjs__fake-timers": {
+      "version": "8.1.5",
+      "resolved": "https://registry.npmjs.org/@types/sinonjs__fake-timers/-/sinonjs__fake-timers-8.1.5.tgz",
+      "integrity": "sha512-mQkU2jY8jJEF7YHjHvsQO8+3ughTL1mcnn96igfhONmR+fUPSKIkefQYpSe8bsly2Ep7oQbn/6VG5/9/0qcArQ==",
+      "dev": true
+    },
+    "node_modules/@types/uuid": {
+      "version": "9.0.7",
+      "resolved": "https://registry.npmjs.org/@types/uuid/-/uuid-9.0.7.tgz",
+      "integrity": "sha512-WUtIVRUZ9i5dYXefDEAI7sh9/O7jGvHg7Df/5O/gtH3Yabe5odI3UWopVR1qbPXQtvOxWu3mM4XxlYeZtMWF4g==",
+      "dev": true
+    },
     "node_modules/@typescript-eslint/eslint-plugin": {
       "version": "6.8.0",
       "resolved": "https://registry.npmjs.org/@typescript-eslint/eslint-plugin/-/eslint-plugin-6.8.0.tgz",
@@ -4152,6 +4182,12 @@
       "integrity": "sha512-U3PUjAudAdJBeC2pgN8uTIKgxrb4nlDF3SF0++EldXQvQBGkpFZMSnwQiIoDU77tv45VgNkl/L4ouD+rEomujw==",
       "dev": true
     },
+    "@types/mocha": {
+      "version": "10.0.4",
+      "resolved": "https://registry.npmjs.org/@types/mocha/-/mocha-10.0.4.tgz",
+      "integrity": "sha512-xKU7bUjiFTIttpWaIZ9qvgg+22O1nmbA+HRxdlR+u6TWsGfmFdXrheJoK4fFxrHNVIOBDvDNKZG+LYBpMHpX3w==",
+      "dev": true
+    },
     "@types/node": {
       "version": "20.8.7",
       "resolved": "https://registry.npmjs.org/@types/node/-/node-20.8.7.tgz",
@@ -4167,6 +4203,27 @@
       "integrity": "sha512-MMzuxN3GdFwskAnb6fz0orFvhfqi752yjaXylr0Rp4oDg5H0Zn1IuyRhDVvYOwAXoJirx2xuS16I3WjxnAIHiQ==",
       "dev": true
     },
+    "@types/sinon": {
+      "version": "17.0.1",
+      "resolved": "https://registry.npmjs.org/@types/sinon/-/sinon-17.0.1.tgz",
+      "integrity": "sha512-Q2Go6TJetYn5Za1+RJA1Aik61Oa2FS8SuJ0juIqUuJ5dZR4wvhKfmSdIqWtQ3P6gljKWjW0/R7FZkA4oXVL6OA==",
+      "dev": true,
+      "requires": {
+        "@types/sinonjs__fake-timers": "*"
+      }
+    },
+    "@types/sinonjs__fake-timers": {
+      "version": "8.1.5",
+      "resolved": "https://registry.npmjs.org/@types/sinonjs__fake-timers/-/sinonjs__fake-timers-8.1.5.tgz",
+      "integrity": "sha512-mQkU2jY8jJEF7YHjHvsQO8+3ughTL1mcnn96igfhONmR+fUPSKIkefQYpSe8bsly2Ep7oQbn/6VG5/9/0qcArQ==",
+      "dev": true
+    },
+    "@types/uuid": {
+      "version": "9.0.7",
+      "resolved": "https://registry.npmjs.org/@types/uuid/-/uuid-9.0.7.tgz",
+      "integrity": "sha512-WUtIVRUZ9i5dYXefDEAI7sh9/O7jGvHg7Df/5O/gtH3Yabe5odI3UWopVR1qbPXQtvOxWu3mM4XxlYeZtMWF4g==",
+      "dev": true
+    },
     "@typescript-eslint/eslint-plugin": {
       "version": "6.8.0",
       "resolved": "https://registry.npmjs.org/@typescript-eslint/eslint-plugin/-/eslint-plugin-6.8.0.tgz",
diff --git a/package.json b/package.json
index b354ca12..7f7ef05e 100644
--- a/package.json
+++ b/package.json
@@ -17,14 +17,15 @@
     "README.md"
   ],
   "scripts": {
-    "build": "npm run clean && npm run build-cjs && npm run build-esm",
+    "build": "npm run clean && npm run build-cjs && npm run build-esm && npm run build-test",
     "build-cjs": "rollup --config",
-    "build-esm": "tsc -p ./",
-    "clean": "rimraf dist dist-esm types",
+    "build-esm": "tsc -p ./tsconfig.json",
+    "build-test": "tsc -p ./tsconfig.test.json",
+    "clean": "rimraf dist dist-esm out types",
     "dev": "rollup --config --watch",
     "lint": "eslint src/ test/",
     "fix-lint": "eslint src/ test/ --fix",
-    "test": "mocha --timeout 10000"
+    "test": "mocha out/test/*.test.{js,cjs,mjs} --timeout 10000"
   },
   "repository": {
     "type": "git",
@@ -33,7 +34,10 @@
   "license": "MIT",
   "devDependencies": {
     "@rollup/plugin-typescript": "^11.1.2",
+    "@types/mocha": "^10.0.4",
     "@types/node": "^20.5.7",
+    "@types/sinon": "^17.0.1",
+    "@types/uuid": "^9.0.7",
     "@typescript-eslint/eslint-plugin": "^6.6.0",
     "@typescript-eslint/parser": "^6.6.0",
     "chai": "^4.3.7",
diff --git a/src/AzureAppConfiguration.ts b/src/AzureAppConfiguration.ts
index cd4cdc2a..a4af8746 100644
--- a/src/AzureAppConfiguration.ts
+++ b/src/AzureAppConfiguration.ts
@@ -3,4 +3,4 @@
 
 export type AzureAppConfiguration = {
     // methods for advanced features, e.g. refresh()
-} & ReadonlyMap<string, unknown>;
+} & ReadonlyMap<string, any>;
diff --git a/test/.eslintrc b/test/.eslintrc
deleted file mode 100644
index a9331162..00000000
--- a/test/.eslintrc
+++ /dev/null
@@ -1,5 +0,0 @@
-{
-    "rules": {
-        "@typescript-eslint/no-var-requires": "off"
-    }
-}
\ No newline at end of file
diff --git a/test/clientOptions.test.js b/test/clientOptions.test.ts
similarity index 86%
rename from test/clientOptions.test.js
rename to test/clientOptions.test.ts
index ebd615b2..c5496fb9 100644
--- a/test/clientOptions.test.js
+++ b/test/clientOptions.test.ts
@@ -1,15 +1,18 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT license.
 
-const chai = require("chai");
-const chaiAsPromised = require("chai-as-promised");
+import * as chai from "chai";
+import * as chaiAsPromised from "chai-as-promised";
 chai.use(chaiAsPromised);
 const expect = chai.expect;
-const { load } = require("../dist/index");
-const { createMockedConnectionString } = require("./utils/testHelper");
-const nock = require("nock");
+import { load } from "./exportedApi";
+import { createMockedConnectionString } from "./utils/testHelper";
+import * as nock from "nock";
 
 class HttpRequestCountPolicy {
+    count: number;
+    name: string;
+
     constructor() {
         this.count = 0;
         this.name = "HttpRequestCountPolicy";
@@ -58,7 +61,7 @@ describe("custom client options", function () {
 
     it("should override default retry options", async () => {
         const countPolicy = new HttpRequestCountPolicy();
-        const loadWithMaxRetries = (maxRetries) => {
+        const loadWithMaxRetries = (maxRetries: number) => {
             return load(createMockedConnectionString(fakeEndpoint), {
                 clientOptions: {
                     additionalPolicies: [{
diff --git a/test/exportedApi.ts b/test/exportedApi.ts
new file mode 100644
index 00000000..7e6feba1
--- /dev/null
+++ b/test/exportedApi.ts
@@ -0,0 +1,4 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+export { load } from "../src";
\ No newline at end of file
diff --git a/test/json.test.js b/test/json.test.ts
similarity index 90%
rename from test/json.test.js
rename to test/json.test.ts
index 24e18de5..4818e9b2 100644
--- a/test/json.test.js
+++ b/test/json.test.ts
@@ -1,18 +1,12 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT license.
 
-const chai = require("chai");
-const chaiAsPromised = require("chai-as-promised");
+import * as chai from "chai";
+import * as chaiAsPromised from "chai-as-promised";
 chai.use(chaiAsPromised);
 const expect = chai.expect;
-const { load } = require("../dist/index");
-const {
-    mockAppConfigurationClientListConfigurationSettings,
-    restoreMocks,
-    createMockedConnectionString,
-    createMockedKeyVaultReference,
-    createMockedJsonKeyValue
-} = require("./utils/testHelper");
+import { load } from "./exportedApi";
+import { mockAppConfigurationClientListConfigurationSettings, restoreMocks, createMockedConnectionString, createMockedKeyVaultReference, createMockedJsonKeyValue } from "./utils/testHelper";
 
 const jsonKeyValue = createMockedJsonKeyValue("json.settings.logging", '{"Test":{"Level":"Debug"},"Prod":{"Level":"Warning"}}');
 const keyVaultKeyValue = createMockedKeyVaultReference("TestKey", "https://fake-vault-name.vault.azure.net/secrets/fakeSecretName");
diff --git a/test/keyvault.test.js b/test/keyvault.test.ts
similarity index 84%
rename from test/keyvault.test.js
rename to test/keyvault.test.ts
index 02d676d7..c5ac332e 100644
--- a/test/keyvault.test.js
+++ b/test/keyvault.test.ts
@@ -1,16 +1,13 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT license.
 
-const chai = require("chai");
-const chaiAsPromised = require("chai-as-promised");
+import * as chai from "chai";
+import * as chaiAsPromised from "chai-as-promised";
 chai.use(chaiAsPromised);
 const expect = chai.expect;
-const { load } = require("../dist/index");
-const { sinon,
-    createMockedConnectionString,
-    createMockedTokenCredential,
-    mockAppConfigurationClientListConfigurationSettings, mockSecretClientGetSecret, restoreMocks, createMockedKeyVaultReference } = require("./utils/testHelper");
-const { SecretClient } = require("@azure/keyvault-secrets");
+import { load } from "./exportedApi";
+import { sinon, createMockedConnectionString, createMockedTokenCredential, mockAppConfigurationClientListConfigurationSettings, mockSecretClientGetSecret, restoreMocks, createMockedKeyVaultReference } from "./utils/testHelper";
+import { KeyVaultSecret, SecretClient } from "@azure/keyvault-secrets";
 
 const mockedData = [
     // key, secretUri, value
@@ -72,9 +69,9 @@ describe("key vault reference", function () {
 
         // mock specific behavior per secret client
         const client1 = new SecretClient("https://fake-vault-name.vault.azure.net", createMockedTokenCredential());
-        sinon.stub(client1, "getSecret").returns({ value: "SecretValueViaClient1" });
+        sinon.stub(client1, "getSecret").returns(Promise.resolve({value: "SecretValueViaClient1" } as KeyVaultSecret));
         const client2 = new SecretClient("https://fake-vault-name2.vault.azure.net", createMockedTokenCredential());
-        sinon.stub(client2, "getSecret").returns({ value: "SecretValueViaClient2" });
+        sinon.stub(client2, "getSecret").returns(Promise.resolve({value: "SecretValueViaClient2" } as KeyVaultSecret));
         const settings = await load(createMockedConnectionString(), {
             keyVaultOptions: {
                 secretClients: [
diff --git a/test/load.test.js b/test/load.test.ts
similarity index 91%
rename from test/load.test.js
rename to test/load.test.ts
index 36d9d8bf..3e3d4c10 100644
--- a/test/load.test.js
+++ b/test/load.test.ts
@@ -1,19 +1,12 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT license.
 
-const chai = require("chai");
-const chaiAsPromised = require("chai-as-promised");
+import * as chai from "chai";
+import * as chaiAsPromised from "chai-as-promised";
 chai.use(chaiAsPromised);
 const expect = chai.expect;
-const { load } = require("../dist/index");
-const {
-    mockAppConfigurationClientListConfigurationSettings,
-    restoreMocks,
-    createMockedConnectionString,
-    createMockedEnpoint,
-    createMockedTokenCredential,
-    createMockedKeyValue,
-} = require("./utils/testHelper");
+import { load } from "./exportedApi";
+import { mockAppConfigurationClientListConfigurationSettings, restoreMocks, createMockedConnectionString, createMockedEnpoint, createMockedTokenCredential, createMockedKeyValue } from "./utils/testHelper";
 
 const mockedKVs = [{
     key: "app.settings.fontColor",
diff --git a/test/requestTracing.test.js b/test/requestTracing.test.ts
similarity index 86%
rename from test/requestTracing.test.js
rename to test/requestTracing.test.ts
index 533cd7a3..aaedae20 100644
--- a/test/requestTracing.test.js
+++ b/test/requestTracing.test.ts
@@ -1,14 +1,16 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT license.
 
-const chai = require("chai");
-const chaiAsPromised = require("chai-as-promised");
+import * as chai from "chai";
+import * as chaiAsPromised from "chai-as-promised";
 chai.use(chaiAsPromised);
 const expect = chai.expect;
-const { load } = require("../dist/index");
-const { createMockedConnectionString, createMockedTokenCredential } = require("./utils/testHelper");
-
+import { createMockedConnectionString, createMockedTokenCredential } from "./utils/testHelper";
+import { load } from "./exportedApi";
 class HttpRequestHeadersPolicy {
+    headers: any;
+    name: string;
+
     constructor() {
         this.headers = {};
         this.name = "HttpRequestHeadersPolicy";
@@ -22,13 +24,14 @@ class HttpRequestHeadersPolicy {
 describe("request tracing", function () {
     const fakeEndpoint = "https://127.0.0.1"; // sufficient to test the request it sends out
     const headerPolicy = new HttpRequestHeadersPolicy();
+    const position: "perCall" | "perRetry" = "perCall";
     const clientOptions = {
         retryOptions: {
             maxRetries: 0 // save time
         },
         additionalPolicies: [{
             policy: headerPolicy,
-            position: "perCall"
+            position
         }]
     };
 
@@ -43,7 +46,7 @@ describe("request tracing", function () {
             await load(createMockedConnectionString(fakeEndpoint), { clientOptions });
         } catch (e) { /* empty */ }
         expect(headerPolicy.headers).not.undefined;
-        expect(headerPolicy.headers.get("User-Agent")).satisfy(ua => ua.startsWith("javascript-appconfiguration-provider"));
+        expect(headerPolicy.headers.get("User-Agent")).satisfy((ua: string) => ua.startsWith("javascript-appconfiguration-provider"));
     });
 
     it("should have request type in correlation-context header", async () => {
@@ -99,7 +102,7 @@ describe("request tracing", function () {
         delete process.env.WEBSITE_SITE_NAME;
     });
 
-    it("should disable request tracing when AZURE_APP_CONFIGURATION_TRACING_DISABLED is true", async() => {
+    it("should disable request tracing when AZURE_APP_CONFIGURATION_TRACING_DISABLED is true", async () => {
         for (const indicator of ["TRUE", "true"]) {
             process.env.AZURE_APP_CONFIGURATION_TRACING_DISABLED = indicator;
             try {
diff --git a/test/utils/testHelper.js b/test/utils/testHelper.ts
similarity index 68%
rename from test/utils/testHelper.js
rename to test/utils/testHelper.ts
index b58aa859..6db4bf62 100644
--- a/test/utils/testHelper.js
+++ b/test/utils/testHelper.ts
@@ -1,47 +1,50 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT license.
 
-const sinon = require("sinon");
-const { AppConfigurationClient } = require("@azure/app-configuration");
-const { ClientSecretCredential } = require("@azure/identity");
-const { SecretClient } = require("@azure/keyvault-secrets");
-const uuid = require("uuid");
+import * as sinon from "sinon";
+import { AppConfigurationClient } from "@azure/app-configuration";
+import { ClientSecretCredential } from "@azure/identity";
+import { KeyVaultSecret, SecretClient } from "@azure/keyvault-secrets";
+import * as uuid from "uuid";
 
-const TEST_CLIENT_ID = "62e76eb5-218e-4f90-8261-000000000000";
-const TEST_TENANT_ID = "72f988bf-86f1-41af-91ab-000000000000";
-const TEST_CLIENT_SECRET = "Q158Q~2JtUwVbuq0Mzm9ocH2umTB000000000000";
+const TEST_CLIENT_ID = "00000000-0000-0000-0000-000000000000";
+const TEST_TENANT_ID = "00000000-0000-0000-0000-000000000000";
+const TEST_CLIENT_SECRET = "0000000000000000000000000000000000000000";
 
-function mockAppConfigurationClientListConfigurationSettings(kvList) {
-    function* testKvSetGnerator(kvs) {
+function mockAppConfigurationClientListConfigurationSettings(kvList: any[]) {
+    function* testKvSetGnerator(kvs: any[]) {
         yield* kvs;
     }
     sinon.stub(AppConfigurationClient.prototype, "listConfigurationSettings").callsFake((listOptions) => {
-        const keyFilter = listOptions.keyFilter ?? "*";
-        const labelFilter = listOptions.labelFilter ?? "*";
+        const keyFilter = listOptions?.keyFilter ?? "*";
+        const labelFilter = listOptions?.labelFilter ?? "*";
         const kvs = kvList.filter(kv => {
             const keyMatched = keyFilter.endsWith("*") ? kv.key.startsWith(keyFilter.slice(0, keyFilter.length - 1)) : kv.key === keyFilter;
             const labelMatched = labelFilter.endsWith("*") ? kv.label.startsWith(labelFilter.slice(0, labelFilter.length - 1))
                 : (labelFilter === "\0" ? kv.label === null : kv.label === labelFilter); // '\0' in labelFilter, null in config setting.
             return keyMatched && labelMatched;
         })
-        return testKvSetGnerator(kvs);
+        return testKvSetGnerator(kvs) as any;
     });
 }
 
 // uriValueList: [["<secretUri>", "value"], ...]
-function mockSecretClientGetSecret(uriValueList) {
+function mockSecretClientGetSecret(uriValueList: [string, string][]) {
     const dict = new Map();
     for (const [uri, value] of uriValueList) {
         dict.set(uri, value);
     }
 
-    sinon.stub(SecretClient.prototype, "getSecret").callsFake(function (secretName, options) {
+    sinon.stub(SecretClient.prototype, "getSecret").callsFake(async function (secretName, options) {
         const url = new URL(this.vaultUrl);
         url.pathname = `/secrets/${secretName}`;
         if (options?.version) {
             url.pathname += `/${options.version}`;
         }
-        return { value: dict.get(url.toString()) };
+        return {
+            name: secretName,
+            value: dict.get(url.toString())
+        } as KeyVaultSecret;
     })
 }
 
@@ -61,7 +64,7 @@ const createMockedTokenCredential = (tenantId = TEST_TENANT_ID, clientId = TEST_
     return new ClientSecretCredential(tenantId, clientId, clientSecret);
 }
 
-const createMockedKeyVaultReference = (key, vaultUri) => ({
+const createMockedKeyVaultReference = (key: string, vaultUri: string) => ({
     // https://${vaultName}.vault.azure.net/secrets/${secretName}
     value: `{"uri":"${vaultUri}"}`,
     key,
@@ -74,7 +77,7 @@ const createMockedKeyVaultReference = (key, vaultUri) => ({
     isReadOnly: false,
 });
 
-const createMockedJsonKeyValue = (key, value) => ({
+const createMockedJsonKeyValue = (key: string, value: any) => ({
     value: value,
     key: key,
     label: null,
@@ -85,7 +88,7 @@ const createMockedJsonKeyValue = (key, value) => ({
     isReadOnly: false
 });
 
-const createMockedKeyValue = (props) => (Object.assign({
+const createMockedKeyValue = (props: {[key: string]: any}) => (Object.assign({
     value: "TestValue",
     key: "TestKey",
     label: null,
@@ -96,7 +99,7 @@ const createMockedKeyValue = (props) => (Object.assign({
     isReadOnly: false
 }, props));
 
-module.exports = {
+export {
     sinon,
     mockAppConfigurationClientListConfigurationSettings,
     mockSecretClientGetSecret,
diff --git a/tsconfig.base.json b/tsconfig.base.json
new file mode 100644
index 00000000..0f96a196
--- /dev/null
+++ b/tsconfig.base.json
@@ -0,0 +1,24 @@
+{
+    "compilerOptions": {
+        "lib": [
+            "DOM",
+            "WebWorker",
+            "ESNext"
+        ],
+        "skipDefaultLibCheck": true,
+        "module": "ESNext",
+        "moduleResolution": "Node",
+        "target": "ES2022",
+        "strictNullChecks": true,
+        "strictFunctionTypes": true,
+        "sourceMap": true,
+        "inlineSources": true
+    },
+    "include": [
+        "src/**/*"
+    ],
+    "exclude": [
+        "node_modules",
+        "**/node_modules/*"
+    ]
+}
\ No newline at end of file
diff --git a/tsconfig.json b/tsconfig.json
index 395c4d54..f2fc0e9b 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -1,25 +1,10 @@
 {
+    "extends": "./tsconfig.base.json",
     "compilerOptions": {
-        "lib": [
-            "DOM",
-            "WebWorker",
-            "ESNext"
-        ],
-        "skipDefaultLibCheck": true,
         "module": "ESNext",
-        "moduleResolution": "Node",
-        "target": "ES2022",
-        "strictNullChecks": true,
-        "strictFunctionTypes": true,
-        "sourceMap": true,
-        "inlineSources": true,
         "outDir": "./dist-esm"
     },
     "include": [
         "src/**/*"
-    ],
-    "exclude": [
-        "node_modules",
-        "**/node_modules/*"
     ]
 }
\ No newline at end of file
diff --git a/tsconfig.test.json b/tsconfig.test.json
new file mode 100644
index 00000000..3cbd3c0a
--- /dev/null
+++ b/tsconfig.test.json
@@ -0,0 +1,10 @@
+{
+    "extends": "./tsconfig.base.json",
+    "compilerOptions": {
+        "module": "CommonJS",
+        "outDir": "./out"
+    },
+    "include": [
+        "test/**/*"
+    ]
+}
\ No newline at end of file

From bae1b0ec8f1317fdba9169caf57a6198f9c9deb0 Mon Sep 17 00:00:00 2001
From: Yan Zhang <2351748+Eskibear@users.noreply.github.com>
Date: Thu, 9 Nov 2023 08:36:32 +0800
Subject: [PATCH 3/8] update @azure/core-rest-pipeline to 1.12.2 (#25)

---
 package-lock.json          | 14 +++++++-------
 test/clientOptions.test.ts | 31 ++++++++++++++++++++++++-------
 2 files changed, 31 insertions(+), 14 deletions(-)

diff --git a/package-lock.json b/package-lock.json
index 9987ca56..d500c31e 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -145,9 +145,9 @@
       }
     },
     "node_modules/@azure/core-rest-pipeline": {
-      "version": "1.12.1",
-      "resolved": "https://registry.npmjs.org/@azure/core-rest-pipeline/-/core-rest-pipeline-1.12.1.tgz",
-      "integrity": "sha512-SsyWQ+T5MFQRX+M8H/66AlaI6HyCbQStGfFngx2fuiW+vKI2DkhtOvbYodPyf9fOe/ARLWWc3ohX54lQ5Kmaog==",
+      "version": "1.12.2",
+      "resolved": "https://registry.npmjs.org/@azure/core-rest-pipeline/-/core-rest-pipeline-1.12.2.tgz",
+      "integrity": "sha512-wLLJQdL4v1yoqYtEtjKNjf8pJ/G/BqVomAWxcKOR1KbZJyCEnCv04yks7Y1NhJ3JzxbDs307W67uX0JzklFdCg==",
       "dependencies": {
         "@azure/abort-controller": "^1.0.0",
         "@azure/core-auth": "^1.4.0",
@@ -160,7 +160,7 @@
         "tslib": "^2.2.0"
       },
       "engines": {
-        "node": ">=14.0.0"
+        "node": ">=16.0.0"
       }
     },
     "node_modules/@azure/core-tracing": {
@@ -3655,9 +3655,9 @@
       }
     },
     "@azure/core-rest-pipeline": {
-      "version": "1.12.1",
-      "resolved": "https://registry.npmjs.org/@azure/core-rest-pipeline/-/core-rest-pipeline-1.12.1.tgz",
-      "integrity": "sha512-SsyWQ+T5MFQRX+M8H/66AlaI6HyCbQStGfFngx2fuiW+vKI2DkhtOvbYodPyf9fOe/ARLWWc3ohX54lQ5Kmaog==",
+      "version": "1.12.2",
+      "resolved": "https://registry.npmjs.org/@azure/core-rest-pipeline/-/core-rest-pipeline-1.12.2.tgz",
+      "integrity": "sha512-wLLJQdL4v1yoqYtEtjKNjf8pJ/G/BqVomAWxcKOR1KbZJyCEnCv04yks7Y1NhJ3JzxbDs307W67uX0JzklFdCg==",
       "requires": {
         "@azure/abort-controller": "^1.0.0",
         "@azure/core-auth": "^1.4.0",
diff --git a/test/clientOptions.test.ts b/test/clientOptions.test.ts
index c5496fb9..2bf146f1 100644
--- a/test/clientOptions.test.ts
+++ b/test/clientOptions.test.ts
@@ -28,12 +28,12 @@ class HttpRequestCountPolicy {
 
 describe("custom client options", function () {
     const fakeEndpoint = "https://azure.azconfig.io";
-    before(() => {
+    beforeEach(() => {
         // Thus here mock it to reply 500, in which case the retry mechanism works.
         nock(fakeEndpoint).persist().get(() => true).reply(500);
     });
 
-    after(() => {
+    afterEach(() => {
         nock.restore();
     })
 
@@ -96,9 +96,26 @@ describe("custom client options", function () {
         expect(countPolicy.count).eq(2);
     });
 
-    // Note:
-    // core-rest-pipeline skips the retry throwing `RestError: getaddrinfo ENOTFOUND azure.azconfig.io`
-    // Probably would be fixed in upstream libs.
-    // See https://github.com/Azure/azure-sdk-for-js/issues/27037
-    it("should retry on DNS failure");
+    it("should retry on DNS failure", async () => {
+        nock.restore(); // stop mocking with 500 error but sending real requests which will fail with ENOTFOUND
+        const countPolicy = new HttpRequestCountPolicy();
+        const loadPromise = () => {
+            return load(createMockedConnectionString(fakeEndpoint), {
+                clientOptions: {
+                    additionalPolicies: [{
+                        policy: countPolicy,
+                        position: "perRetry"
+                    }]
+                }
+            })
+        };
+        let error;
+        try {
+            await loadPromise();
+        } catch (e) {
+            error = e;
+        }
+        expect(error).not.undefined;
+        expect(countPolicy.count).eq(3);
+    });
 })

From 84637e1b30174adba2bbf381484a31cbe584bedc Mon Sep 17 00:00:00 2001
From: Yan Zhang <2351748+Eskibear@users.noreply.github.com>
Date: Thu, 9 Nov 2023 08:36:47 +0800
Subject: [PATCH 4/8] update CI: Node.js 16.x end-of-life (#26)

---
 .github/workflows/ci.yml | 2 +-
 azure-pipelines.yml      | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 613b189e..81490d40 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -13,7 +13,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [16.x, 18.x, 20.x]
+        node-version: [18.x, 20.x]
 
     steps:
     - uses: actions/checkout@v3
diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index 53ac8f1e..f1925cb2 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -12,7 +12,7 @@ pool:
 steps:
 - task: NodeTool@0
   inputs:
-    versionSpec: '16.x'
+    versionSpec: '18.x'
   displayName: 'Install Node.js'
 
 - script: |

From aded5bb33837706df569b3b6fbc034b8c72d0e2f Mon Sep 17 00:00:00 2001
From: Yan Zhang <2351748+Eskibear@users.noreply.github.com>
Date: Thu, 9 Nov 2023 09:39:06 +0800
Subject: [PATCH 5/8] update @azure/app-configuration to 1.5.0 (#27)

---
 package-lock.json | 45 ++++++++++++++++++++++++++++++++++++---------
 package.json      |  2 +-
 2 files changed, 37 insertions(+), 10 deletions(-)

diff --git a/package-lock.json b/package-lock.json
index d500c31e..398cff78 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -9,7 +9,7 @@
       "version": "1.0.0-preview",
       "license": "MIT",
       "dependencies": {
-        "@azure/app-configuration": "^1.4.1",
+        "@azure/app-configuration": "^1.5.0",
         "@azure/identity": "^3.3.2",
         "@azure/keyvault-secrets": "^4.7.0"
       },
@@ -57,14 +57,15 @@
       }
     },
     "node_modules/@azure/app-configuration": {
-      "version": "1.4.1",
-      "resolved": "https://registry.npmjs.org/@azure/app-configuration/-/app-configuration-1.4.1.tgz",
-      "integrity": "sha512-9vLmveQR3U5DmMGkXU6fQzG7vf+GWMM+1g6zf/5Ro81dOP0R2fPDdBOd4Edg2pZpuswsf2t6QE+wo/oCeaVLZA==",
+      "version": "1.5.0",
+      "resolved": "https://registry.npmjs.org/@azure/app-configuration/-/app-configuration-1.5.0.tgz",
+      "integrity": "sha512-YlXwWc/weDFCk12arPkfskXDGxDaSyAA7JaztSVQ0y/IS7GFYqmIj3RTKbsNUSSuGLrKqcxwJ7y3vY9UmHgsdA==",
       "dependencies": {
         "@azure/abort-controller": "^1.0.0",
         "@azure/core-auth": "^1.3.0",
         "@azure/core-client": "^1.5.0",
-        "@azure/core-http-compat": "^1.2.0",
+        "@azure/core-http-compat": "^2.0.0",
+        "@azure/core-lro": "^2.5.1",
         "@azure/core-paging": "^1.4.0",
         "@azure/core-rest-pipeline": "^1.6.0",
         "@azure/core-tracing": "^1.0.0",
@@ -72,6 +73,19 @@
         "@azure/logger": "^1.0.0",
         "tslib": "^2.2.0"
       },
+      "engines": {
+        "node": ">=18.0.0"
+      }
+    },
+    "node_modules/@azure/app-configuration/node_modules/@azure/core-http-compat": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/@azure/core-http-compat/-/core-http-compat-2.0.1.tgz",
+      "integrity": "sha512-xpQZz/q7E0jSW4rckrTo2mDFDQgo6I69hBU4voMQi7REi6JRW5a+KfVkbJCFCWnkFmP6cAJ0IbuudTdf/MEBOQ==",
+      "dependencies": {
+        "@azure/abort-controller": "^1.0.4",
+        "@azure/core-client": "^1.3.0",
+        "@azure/core-rest-pipeline": "^1.3.0"
+      },
       "engines": {
         "node": ">=14.0.0"
       }
@@ -3585,20 +3599,33 @@
       }
     },
     "@azure/app-configuration": {
-      "version": "1.4.1",
-      "resolved": "https://registry.npmjs.org/@azure/app-configuration/-/app-configuration-1.4.1.tgz",
-      "integrity": "sha512-9vLmveQR3U5DmMGkXU6fQzG7vf+GWMM+1g6zf/5Ro81dOP0R2fPDdBOd4Edg2pZpuswsf2t6QE+wo/oCeaVLZA==",
+      "version": "1.5.0",
+      "resolved": "https://registry.npmjs.org/@azure/app-configuration/-/app-configuration-1.5.0.tgz",
+      "integrity": "sha512-YlXwWc/weDFCk12arPkfskXDGxDaSyAA7JaztSVQ0y/IS7GFYqmIj3RTKbsNUSSuGLrKqcxwJ7y3vY9UmHgsdA==",
       "requires": {
         "@azure/abort-controller": "^1.0.0",
         "@azure/core-auth": "^1.3.0",
         "@azure/core-client": "^1.5.0",
-        "@azure/core-http-compat": "^1.2.0",
+        "@azure/core-http-compat": "^2.0.0",
+        "@azure/core-lro": "^2.5.1",
         "@azure/core-paging": "^1.4.0",
         "@azure/core-rest-pipeline": "^1.6.0",
         "@azure/core-tracing": "^1.0.0",
         "@azure/core-util": "^1.1.0",
         "@azure/logger": "^1.0.0",
         "tslib": "^2.2.0"
+      },
+      "dependencies": {
+        "@azure/core-http-compat": {
+          "version": "2.0.1",
+          "resolved": "https://registry.npmjs.org/@azure/core-http-compat/-/core-http-compat-2.0.1.tgz",
+          "integrity": "sha512-xpQZz/q7E0jSW4rckrTo2mDFDQgo6I69hBU4voMQi7REi6JRW5a+KfVkbJCFCWnkFmP6cAJ0IbuudTdf/MEBOQ==",
+          "requires": {
+            "@azure/abort-controller": "^1.0.4",
+            "@azure/core-client": "^1.3.0",
+            "@azure/core-rest-pipeline": "^1.3.0"
+          }
+        }
       }
     },
     "@azure/core-auth": {
diff --git a/package.json b/package.json
index 7f7ef05e..74eca211 100644
--- a/package.json
+++ b/package.json
@@ -55,7 +55,7 @@
     "uuid": "^9.0.1"
   },
   "dependencies": {
-    "@azure/app-configuration": "^1.4.1",
+    "@azure/app-configuration": "^1.5.0",
     "@azure/identity": "^3.3.2",
     "@azure/keyvault-secrets": "^4.7.0"
   }

From 8d4187dc8f436232a2c4ce4592d095191204e784 Mon Sep 17 00:00:00 2001
From: Yan Zhang <2351748+Eskibear@users.noreply.github.com>
Date: Fri, 10 Nov 2023 03:06:31 +0800
Subject: [PATCH 6/8] Update mocked func for app-configuration v1.5.0 (#28)

---
 test/utils/testHelper.ts | 34 ++++++++++++++++++++--------------
 1 file changed, 20 insertions(+), 14 deletions(-)

diff --git a/test/utils/testHelper.ts b/test/utils/testHelper.ts
index 6db4bf62..679069c4 100644
--- a/test/utils/testHelper.ts
+++ b/test/utils/testHelper.ts
@@ -2,7 +2,7 @@
 // Licensed under the MIT license.
 
 import * as sinon from "sinon";
-import { AppConfigurationClient } from "@azure/app-configuration";
+import { AppConfigurationClient, ConfigurationSetting } from "@azure/app-configuration";
 import { ClientSecretCredential } from "@azure/identity";
 import { KeyVaultSecret, SecretClient } from "@azure/keyvault-secrets";
 import * as uuid from "uuid";
@@ -11,7 +11,7 @@ const TEST_CLIENT_ID = "00000000-0000-0000-0000-000000000000";
 const TEST_TENANT_ID = "00000000-0000-0000-0000-000000000000";
 const TEST_CLIENT_SECRET = "0000000000000000000000000000000000000000";
 
-function mockAppConfigurationClientListConfigurationSettings(kvList: any[]) {
+function mockAppConfigurationClientListConfigurationSettings(kvList: ConfigurationSetting[]) {
     function* testKvSetGnerator(kvs: any[]) {
         yield* kvs;
     }
@@ -19,9 +19,18 @@ function mockAppConfigurationClientListConfigurationSettings(kvList: any[]) {
         const keyFilter = listOptions?.keyFilter ?? "*";
         const labelFilter = listOptions?.labelFilter ?? "*";
         const kvs = kvList.filter(kv => {
-            const keyMatched = keyFilter.endsWith("*") ? kv.key.startsWith(keyFilter.slice(0, keyFilter.length - 1)) : kv.key === keyFilter;
-            const labelMatched = labelFilter.endsWith("*") ? kv.label.startsWith(labelFilter.slice(0, labelFilter.length - 1))
-                : (labelFilter === "\0" ? kv.label === null : kv.label === labelFilter); // '\0' in labelFilter, null in config setting.
+            const keyMatched = keyFilter.endsWith("*") ? kv.key.startsWith(keyFilter.slice(0, -1)) : kv.key === keyFilter;
+
+            let labelMatched = false;
+            if (labelFilter === "*") {
+                labelMatched = true;
+            } else if (labelFilter === "\0") {
+                labelMatched = kv.label === undefined;
+            } else if (labelFilter.endsWith("*")) {
+                labelMatched = kv.label !== undefined && kv.label.startsWith(labelFilter.slice(0, -1));
+            } else {
+                labelMatched = kv.label === labelFilter;
+            }
             return keyMatched && labelMatched;
         })
         return testKvSetGnerator(kvs) as any;
@@ -64,36 +73,33 @@ const createMockedTokenCredential = (tenantId = TEST_TENANT_ID, clientId = TEST_
     return new ClientSecretCredential(tenantId, clientId, clientSecret);
 }
 
-const createMockedKeyVaultReference = (key: string, vaultUri: string) => ({
+const createMockedKeyVaultReference = (key: string, vaultUri: string): ConfigurationSetting => ({
     // https://${vaultName}.vault.azure.net/secrets/${secretName}
     value: `{"uri":"${vaultUri}"}`,
     key,
-    label: null,
     contentType: "application/vnd.microsoft.appconfig.keyvaultref+json;charset=utf-8",
-    lastModified: "2023-05-09T08:51:11.000Z",
+    lastModified: new Date(),
     tags: {
     },
     etag: "SPJSMnJ2ph4BAjftWfdIctV2VIyQxtcIzRbh1oxTBkM",
     isReadOnly: false,
 });
 
-const createMockedJsonKeyValue = (key: string, value: any) => ({
+const createMockedJsonKeyValue = (key: string, value: any): ConfigurationSetting => ({
     value: value,
     key: key,
-    label: null,
     contentType: "application/json",
-    lastModified: "2023-05-04T04:32:56.000Z",
+    lastModified: new Date(),
     tags: {},
     etag: "GdmsLWq3mFjFodVEXUYRmvFr3l_qRiKAW_KdpFbxZKk",
     isReadOnly: false
 });
 
-const createMockedKeyValue = (props: {[key: string]: any}) => (Object.assign({
+const createMockedKeyValue = (props: {[key: string]: any}): ConfigurationSetting => (Object.assign({
     value: "TestValue",
     key: "TestKey",
-    label: null,
     contentType: "",
-    lastModified: new Date().toISOString(),
+    lastModified: new Date(),
     tags: {},
     etag: uuid.v4(),
     isReadOnly: false

From 33f033e0a8216ae99e01deefc090935aeaded708 Mon Sep 17 00:00:00 2001
From: Yan Zhang <2351748+Eskibear@users.noreply.github.com>
Date: Tue, 28 Nov 2023 09:48:26 +0800
Subject: [PATCH 7/8] add TSdoc for public API and types (#32)

---
 src/AzureAppConfigurationOptions.ts              | 14 ++++++++++++++
 .../AzureAppConfigurationKeyVaultOptions.ts      | 16 ++++++++++++++++
 src/load.ts                                      | 11 +++++++++++
 3 files changed, 41 insertions(+)

diff --git a/src/AzureAppConfigurationOptions.ts b/src/AzureAppConfigurationOptions.ts
index 11a9ba5b..de3b6da3 100644
--- a/src/AzureAppConfigurationOptions.ts
+++ b/src/AzureAppConfigurationOptions.ts
@@ -28,7 +28,21 @@ export interface AzureAppConfigurationOptions {
      * Backslash `\` character is reserved and must be escaped using another backslash `\`.
      */
     selectors?: { keyFilter: string, labelFilter?: string }[];
+
+    /**
+     * Specifies prefixes to be trimmed from the keys of all key-values retrieved from Azure App Configuration.
+     * This is useful when you want to remove a common prefix from all keys to avoid repetition.
+     * The provided prefixes will be sorted in descending order and the longest matching prefix will be trimmed first.
+     */
     trimKeyPrefixes?: string[];
+
+    /**
+     * Specifies custom options to be used when creating the AppConfigurationClient.
+     */
     clientOptions?: AppConfigurationClientOptions;
+
+    /**
+     * Specifies options used to resolve Vey Vault references.
+     */
     keyVaultOptions?: AzureAppConfigurationKeyVaultOptions;
 }
\ No newline at end of file
diff --git a/src/keyvault/AzureAppConfigurationKeyVaultOptions.ts b/src/keyvault/AzureAppConfigurationKeyVaultOptions.ts
index 9b85beef..2b5c7d87 100644
--- a/src/keyvault/AzureAppConfigurationKeyVaultOptions.ts
+++ b/src/keyvault/AzureAppConfigurationKeyVaultOptions.ts
@@ -4,8 +4,24 @@
 import { TokenCredential } from "@azure/identity";
 import { SecretClient } from "@azure/keyvault-secrets";
 
+/**
+ * Options used to resolve Key Vault references.
+ */
 export interface AzureAppConfigurationKeyVaultOptions {
+    /**
+     * Specifies the Key Vault secret client used for resolving Key Vault references.
+     */
     secretClients?: SecretClient[];
+
+    /**
+     * Specifies the credentials used to authenticate to key vaults that have no applied SecretClient.
+     */
     credential?: TokenCredential;
+
+    /**
+     * Specifies the callback used to resolve key vault references that have no applied SecretClient.
+     * @param keyVaultReference The Key Vault reference to resolve.
+     * @returns The secret value.
+     */
     secretResolver?: (keyVaultReference: URL) => string | Promise<string>;
 }
\ No newline at end of file
diff --git a/src/load.ts b/src/load.ts
index dbb64196..a44d4042 100644
--- a/src/load.ts
+++ b/src/load.ts
@@ -8,7 +8,18 @@ import { AzureAppConfigurationImpl } from "./AzureAppConfigurationImpl";
 import { AzureAppConfigurationOptions, MaxRetries, MaxRetryDelayInMs } from "./AzureAppConfigurationOptions";
 import * as RequestTracing from "./requestTracing/constants";
 
+/**
+ * Loads the data from Azure App Configuration service and returns an instance of AzureAppConfiguration.
+ * @param connectionString  The connection string for the App Configuration store.
+ * @param options  Optional parameters.
+ */
 export async function load(connectionString: string, options?: AzureAppConfigurationOptions): Promise<AzureAppConfiguration>;
+/**
+ * Loads the data from Azure App Configuration service and returns an instance of AzureAppConfiguration.
+ * @param endpoint  The URL to the App Configuration store.
+ * @param credential  The credential to use to connect to the App Configuration store.
+ * @param options  Optional parameters.
+ */
 export async function load(endpoint: URL | string, credential: TokenCredential, options?: AzureAppConfigurationOptions): Promise<AzureAppConfiguration>;
 export async function load(
     connectionStringOrEndpoint: string | URL,

From e8292076d5d25f9b8aa17f4200434c905c19958c Mon Sep 17 00:00:00 2001
From: Yan Zhang <2351748+Eskibear@users.noreply.github.com>
Date: Thu, 30 Nov 2023 14:26:36 +0800
Subject: [PATCH 8/8] Dedup exact same selectors while keep original precedence
 (#31)

---
 src/AzureAppConfigurationImpl.ts    | 19 ++++++++++---
 src/AzureAppConfigurationOptions.ts | 22 +++------------
 src/KeyFilter.ts                    |  6 ----
 src/LabelFilter.ts                  |  6 ----
 src/index.ts                        |  3 +-
 src/types.ts                        | 44 +++++++++++++++++++++++++++++
 test/load.test.ts                   | 22 ++++++++++++++-
 7 files changed, 85 insertions(+), 37 deletions(-)
 delete mode 100644 src/KeyFilter.ts
 delete mode 100644 src/LabelFilter.ts
 create mode 100644 src/types.ts

diff --git a/src/AzureAppConfigurationImpl.ts b/src/AzureAppConfigurationImpl.ts
index faaf2524..3c682502 100644
--- a/src/AzureAppConfigurationImpl.ts
+++ b/src/AzureAppConfigurationImpl.ts
@@ -6,11 +6,11 @@ import { AzureAppConfiguration } from "./AzureAppConfiguration";
 import { AzureAppConfigurationOptions } from "./AzureAppConfigurationOptions";
 import { IKeyValueAdapter } from "./IKeyValueAdapter";
 import { JsonKeyValueAdapter } from "./JsonKeyValueAdapter";
-import { KeyFilter } from "./KeyFilter";
-import { LabelFilter } from "./LabelFilter";
+import { KeyFilter, LabelFilter } from "./types";
 import { AzureKeyVaultKeyValueAdapter } from "./keyvault/AzureKeyVaultKeyValueAdapter";
 import { CorrelationContextHeaderName } from "./requestTracing/constants";
 import { createCorrelationContextHeader, requestTracingEnabled } from "./requestTracing/utils";
+import { SettingSelector } from "./types";
 
 export class AzureAppConfigurationImpl extends Map<string, unknown> implements AzureAppConfiguration {
     private adapters: IKeyValueAdapter[] = [];
@@ -109,12 +109,23 @@ export class AzureAppConfigurationImpl extends Map<string, unknown> implements A
     }
 }
 
-function getValidSelectors(selectors?: { keyFilter: string, labelFilter?: string }[]) {
+function getValidSelectors(selectors?: SettingSelector[]) {
     if (!selectors || selectors.length === 0) {
         // Default selector: key: *, label: \0
         return [{ keyFilter: KeyFilter.Any, labelFilter: LabelFilter.Null }];
     }
-    return selectors.map(selectorCandidate => {
+
+    // below code dedupes selectors by keyFilter and labelFilter, the latter selector wins
+    const dedupedSelectors: SettingSelector[] = [];
+    for (const selector of selectors) {
+        const existingSelectorIndex = dedupedSelectors.findIndex(s => s.keyFilter === selector.keyFilter && s.labelFilter === selector.labelFilter);
+        if (existingSelectorIndex >= 0) {
+            dedupedSelectors.splice(existingSelectorIndex, 1);
+        }
+        dedupedSelectors.push(selector);
+    }
+
+    return dedupedSelectors.map(selectorCandidate => {
         const selector = { ...selectorCandidate };
         if (!selector.keyFilter) {
             throw new Error("Key filter cannot be null or empty.");
diff --git a/src/AzureAppConfigurationOptions.ts b/src/AzureAppConfigurationOptions.ts
index de3b6da3..5da5fd18 100644
--- a/src/AzureAppConfigurationOptions.ts
+++ b/src/AzureAppConfigurationOptions.ts
@@ -3,31 +3,17 @@
 
 import { AppConfigurationClientOptions } from "@azure/app-configuration";
 import { AzureAppConfigurationKeyVaultOptions } from "./keyvault/AzureAppConfigurationKeyVaultOptions";
+import { SettingSelector } from "./types";
 
 export const MaxRetries = 2;
 export const MaxRetryDelayInMs = 60000;
 
 export interface AzureAppConfigurationOptions {
     /**
-     * Specify what key-values to include in the configuration provider.  include multiple sets of key-values
-     *
-     * @property keyFilter:
-     * The key filter to apply when querying Azure App Configuration for key-values.
-     * An asterisk `*` can be added to the end to return all key-values whose key begins with the key filter.
-     * e.g. key filter `abc*` returns all key-values whose key starts with `abc`.
-     * A comma `,` can be used to select multiple key-values. Comma separated filters must exactly match a key to select it.
-     * Using asterisk to select key-values that begin with a key filter while simultaneously using comma separated key filters is not supported.
-     * E.g. the key filter `abc*,def` is not supported. The key filters `abc*` and `abc,def` are supported.
-     * For all other cases the characters: asterisk `*`, comma `,`, and backslash `\` are reserved. Reserved characters must be escaped using a backslash (\).
-     * e.g. the key filter `a\\b\,\*c*` returns all key-values whose key starts with `a\b,*c`.
-     *
-     * @property labelFilter:
-     * The label filter to apply when querying Azure App Configuration for key-values.
-     * By default, the "null label" will be used, matching key-values without a label.
-     * The characters asterisk `*` and comma `,` are not supported.
-     * Backslash `\` character is reserved and must be escaped using another backslash `\`.
+     * Specify what key-values to include in the configuration provider.
+     * If no selectors are specified then all key-values with no label will be included.
      */
-    selectors?: { keyFilter: string, labelFilter?: string }[];
+    selectors?: SettingSelector[];
 
     /**
      * Specifies prefixes to be trimmed from the keys of all key-values retrieved from Azure App Configuration.
diff --git a/src/KeyFilter.ts b/src/KeyFilter.ts
deleted file mode 100644
index ff7366ea..00000000
--- a/src/KeyFilter.ts
+++ /dev/null
@@ -1,6 +0,0 @@
-// Copyright (c) Microsoft Corporation.
-// Licensed under the MIT license.
-
-export enum KeyFilter {
-    Any = "*"
-}
\ No newline at end of file
diff --git a/src/LabelFilter.ts b/src/LabelFilter.ts
deleted file mode 100644
index ebb8361a..00000000
--- a/src/LabelFilter.ts
+++ /dev/null
@@ -1,6 +0,0 @@
-// Copyright (c) Microsoft Corporation.
-// Licensed under the MIT license.
-
-export enum LabelFilter {
-    Null = "\0"
-}
\ No newline at end of file
diff --git a/src/index.ts b/src/index.ts
index b2dc467b..524dbec7 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -3,5 +3,4 @@
 
 export { load } from "./load";
 export { AzureAppConfiguration } from "./AzureAppConfiguration";
-export { KeyFilter } from "./KeyFilter";
-export { LabelFilter } from "./LabelFilter";
\ No newline at end of file
+export { KeyFilter, LabelFilter } from "./types";
\ No newline at end of file
diff --git a/src/types.ts b/src/types.ts
new file mode 100644
index 00000000..0b51f905
--- /dev/null
+++ b/src/types.ts
@@ -0,0 +1,44 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+/**
+ * SettingSelector is used to select key-values from Azure App Configuration.
+ * It is used to filter key-values based on keys and labels.
+ * 
+ * @property keyFilter:
+ * The key filter to apply when querying Azure App Configuration for key-values.
+ * An asterisk `*` can be added to the end to return all key-values whose key begins with the key filter.
+ * e.g. key filter `abc*` returns all key-values whose key starts with `abc`.
+ * A comma `,` can be used to select multiple key-values. Comma separated filters must exactly match a key to select it.
+ * Using asterisk to select key-values that begin with a key filter while simultaneously using comma separated key filters is not supported.
+ * E.g. the key filter `abc*,def` is not supported. The key filters `abc*` and `abc,def` are supported.
+ * For all other cases the characters: asterisk `*`, comma `,`, and backslash `\` are reserved. Reserved characters must be escaped using a backslash (\).
+ * e.g. the key filter `a\\b\,\*c*` returns all key-values whose key starts with `a\b,*c`.
+ *
+ * @property labelFilter:
+ * The label filter to apply when querying Azure App Configuration for key-values.
+ * By default, the "null label" will be used, matching key-values without a label.
+ * The characters asterisk `*` and comma `,` are not supported.
+ * Backslash `\` character is reserved and must be escaped using another backslash `\`.
+ */
+export type SettingSelector = { keyFilter: string, labelFilter?: string };
+
+/**
+ * KeyFilter is used to filter key-values based on keys.
+ *
+ * @property Any:
+ * Matches all key-values.
+ */
+export enum KeyFilter {
+    Any = "*"
+}
+
+/**
+ * LabelFilter is used to filter key-values based on labels.
+ *
+ * @property Null:
+ * Matches key-values without a label.
+ */
+export enum LabelFilter {
+    Null = "\0"
+}
diff --git a/test/load.test.ts b/test/load.test.ts
index 3e3d4c10..a0b89691 100644
--- a/test/load.test.ts
+++ b/test/load.test.ts
@@ -151,4 +151,24 @@ describe("load", function () {
         expect(settings.has("TestKey")).eq(true);
         expect(settings.get("TestKey")).eq("TestValueForProd");
     });
-})
+
+    it("should dedup exact same selectors but keeping the precedence", async () => {
+        const connectionString = createMockedConnectionString();
+        const settings = await load(connectionString, {
+            selectors: [{
+                keyFilter: "Test*",
+                labelFilter: "Prod"
+            }, {
+                keyFilter: "Test*",
+                labelFilter: "Test"
+            }, {
+                keyFilter: "Test*",
+                labelFilter: "Prod"
+            }]
+        });
+        expect(settings).not.undefined;
+        expect(settings.has("TestKey")).eq(true);
+        expect(settings.get("TestKey")).eq("TestValueForProd");
+    });
+
+});