Refactor AzureAppConfiguration with new interfaces

src/AzureAppConfiguration.ts

@@ -16,4 +16,29 @@ export type AzureAppConfiguration = {
      * @param thisArg - Optional. Value to use as `this` when executing callback.
      */
     onRefresh(listener: () => any, thisArg?: any): Disposable;
-} & ReadonlyMap<string, any>;
+} & IGettable & IConfigurationObject;
+
+interface IConfigurationObject {
+    /**
+     * Construct configuration object based on Map-styled data structure and hierarchical keys.
+     * @param options - The options to control the conversion behavior.
+     */
+    constructConfigurationObject(options?: ConfigurationObjectConstructionOptions): Record<string, any>;
+}
+
+export interface ConfigurationObjectConstructionOptions {
+    /**
+     * The separator to use when converting hierarchical keys to object properties.
+     * If separator is undefined, '.' will be used by default.
+
+     */
+    separator?: string;
+}
+
+interface IGettable {
+    /**
+     * Get the value of a key-value from the Map-styled data structure.
+     * @param key - The key of the key-value to be retrieved.
+     */
+    get<T>(key: string): T | undefined;
+}

src/AzureAppConfigurationImpl.ts

@@ -3,7 +3,7 @@
 
 import { AppConfigurationClient, ConfigurationSetting, ConfigurationSettingId, GetConfigurationSettingOptions, GetConfigurationSettingResponse, ListConfigurationSettingsOptions } from "@azure/app-configuration";
 import { RestError } from "@azure/core-rest-pipeline";
-import { AzureAppConfiguration } from "./AzureAppConfiguration";
+import { AzureAppConfiguration, ConfigurationObjectConstructionOptions } from "./AzureAppConfiguration";
 import { AzureAppConfigurationOptions } from "./AzureAppConfigurationOptions";
 import { IKeyValueAdapter } from "./IKeyValueAdapter";
 import { JsonKeyValueAdapter } from "./JsonKeyValueAdapter";
@@ -15,7 +15,12 @@ import { CorrelationContextHeaderName } from "./requestTracing/constants";
 import { createCorrelationContextHeader, requestTracingEnabled } from "./requestTracing/utils";
 import { KeyFilter, LabelFilter, SettingSelector } from "./types";
 
-export class AzureAppConfigurationImpl extends Map<string, any> implements AzureAppConfiguration {
+export class AzureAppConfigurationImpl implements AzureAppConfiguration {
+    /**
+     * Hosting key-value pairs in the configuration store.
+     */
+    #configMap: Map<string, any> = new Map<string, any>();
+
     #adapters: IKeyValueAdapter[] = [];
     /**
      * Trim key prefixes sorted in descending order.
@@ -40,7 +45,6 @@ export class AzureAppConfigurationImpl extends Map<string, any> implements Azure
         client: AppConfigurationClient,
         options: AzureAppConfigurationOptions | undefined
     ) {
-        super();
         this.#client = client;
         this.#options = options;
 
@@ -87,6 +91,9 @@ export class AzureAppConfigurationImpl extends Map<string, any> implements Azure
         this.#adapters.push(new JsonKeyValueAdapter());
     }
 
+    get<T>(key: string): T | undefined {
+        return this.#configMap.get(key);
+    }
 
     get #refreshEnabled(): boolean {
         return !!this.#options?.refreshOptions?.enabled;
@@ -157,9 +164,9 @@ export class AzureAppConfigurationImpl extends Map<string, any> implements Azure
             keyValues.push([key, value]);
         }
 
-        this.clear(); // clear existing key-values in case of configuration setting deletion
+        this.#configMap.clear(); // clear existing key-values in case of configuration setting deletion
         for (const [k, v] of keyValues) {
-            this.set(k, v);
+            this.#configMap.set(k, v);
         }
     }
 
@@ -168,11 +175,44 @@ export class AzureAppConfigurationImpl extends Map<string, any> implements Azure
      */
     async load() {
         await this.#loadSelectedAndWatchedKeyValues();
-
         // Mark all settings have loaded at startup.
         this.#isInitialLoadCompleted = true;
     }
 
+    /**
+     * Construct hierarchical data object from map.
+     */
+    constructConfigurationObject(options?: ConfigurationObjectConstructionOptions): Record<string, any> {
+        const separator = options?.separator ?? ".";
+
+        // construct hierarchical data object from map
+        const data: Record<string, any> = {};
+        for (const [key, value] of this.#configMap) {
+            const segments = key.split(separator);
+            let current = data;
+            // construct hierarchical data object along the path
+            for (let i = 0; i < segments.length - 1; i++) {
+                const segment = segments[i];
+                // undefined or empty string
+                if (!segment) {
+                    throw new Error(`invalid key: ${key}`);
+                }
+                // create path if not exist
+                if (current[segment] === undefined) {
+                    current[segment] = {};
+                }
+                // The path has been occupied by a non-object value, causing ambiguity.
+                if (typeof current[segment] !== "object") {
+                    throw new Error(`The key '${segments.slice(0, i + 1).join(separator)}' is not a valid path.`);
+                }
+                current = current[segment];
+            }
+            // set value to the last segment
+            current[segments[segments.length - 1]] = value;
+        }
+        return data;
+    }
+
     /**
      * Refresh the configuration store.
      */

test/json.test.ts

@@ -25,7 +25,7 @@ describe("json", function () {
         const connectionString = createMockedConnectionString();
         const settings = await load(connectionString);
         expect(settings).not.undefined;
-        const logging = settings.get("json.settings.logging");
+        const logging = settings.get<any>("json.settings.logging");
         expect(logging).not.undefined;
         expect(logging.Test).not.undefined;
         expect(logging.Test.Level).eq("Debug");
@@ -43,7 +43,7 @@ describe("json", function () {
             }
         });
         expect(settings).not.undefined;
-        const resolvedSecret = settings.get("TestKey");
+        const resolvedSecret = settings.get<any>("TestKey");
         expect(resolvedSecret).not.undefined;
         expect(resolvedSecret.uri).undefined;
         expect(typeof resolvedSecret).eq("string");
@@ -74,7 +74,7 @@ describe("json", function () {
         const settings = await load(connectionString);
         expect(settings).not.undefined;
         expect(typeof settings.get("json.settings.object")).eq("object", "is object");
-        expect(Object.keys(settings.get("json.settings.object")).length).eq(0, "is empty object");
+        expect(Object.keys(settings.get<any>("json.settings.object")).length).eq(0, "is empty object");
         expect(Array.isArray(settings.get("json.settings.array"))).eq(true, "is array");
         expect(settings.get("json.settings.number")).eq(8, "is number");
         expect(settings.get("json.settings.string")).eq("string", "is string");

test/load.test.ts

@@ -28,7 +28,24 @@ const mockedKVs = [{
 }, {
     key: "KeyForEmptyValue",
     value: "",
-}].map(createMockedKeyValue);
+}, {
+    key: "app2.settings",
+    value: JSON.stringify({ fontColor: "blue", fontSize: 20 }),
+    contentType: "application/json"
+}, {
+    key: "app3.settings",
+    value: "placeholder"
+}, {
+    key: "app3.settings.fontColor",
+    value: "yellow"
+}, {
+    key: "app4.excludedFolders.0",
+    value: "node_modules"
+}, {
+    key: "app4.excludedFolders.1",
+    value: "dist"
+}
+].map(createMockedKeyValue);
 
 describe("load", function () {
     this.timeout(10000);
@@ -85,11 +102,8 @@ describe("load", function () {
             trimKeyPrefixes: ["app.settings."]
         });
         expect(settings).not.undefined;
-        expect(settings.has("fontColor")).eq(true);
         expect(settings.get("fontColor")).eq("red");
-        expect(settings.has("fontSize")).eq(true);
         expect(settings.get("fontSize")).eq("40");
-        expect(settings.has("TestKey")).eq(false);
     });
 
     it("should trim longest key prefix first", async () => {
@@ -102,20 +116,15 @@ describe("load", function () {
             trimKeyPrefixes: ["app.", "app.settings.", "Test"]
         });
         expect(settings).not.undefined;
-        expect(settings.has("fontColor")).eq(true);
         expect(settings.get("fontColor")).eq("red");
-        expect(settings.has("fontSize")).eq(true);
         expect(settings.get("fontSize")).eq("40");
-        expect(settings.has("TestKey")).eq(false);
     });
 
     it("should support null/empty value", async () => {
         const connectionString = createMockedConnectionString();
         const settings = await load(connectionString);
         expect(settings).not.undefined;
-        expect(settings.has("KeyForNullValue")).eq(true);
         expect(settings.get("KeyForNullValue")).eq(null);
-        expect(settings.has("KeyForEmptyValue")).eq(true);
         expect(settings.get("KeyForEmptyValue")).eq("");
     });
 
@@ -153,7 +162,6 @@ describe("load", function () {
             }]
         });
         expect(settings).not.undefined;
-        expect(settings.has("TestKey")).eq(true);
         expect(settings.get("TestKey")).eq("TestValueForProd");
     });
 
@@ -172,8 +180,84 @@ describe("load", function () {
             }]
         });
         expect(settings).not.undefined;
-        expect(settings.has("TestKey")).eq(true);
         expect(settings.get("TestKey")).eq("TestValueForProd");
     });
 
+    // access data property
+    it("should directly access data property", async () => {
+        const connectionString = createMockedConnectionString();
+        const settings = await load(connectionString, {
+            selectors: [{
+                keyFilter: "app.settings.*"
+            }]
+        });
+        expect(settings).not.undefined;
+        const data = settings.constructConfigurationObject();
+        expect(data).not.undefined;
+        expect(data.app.settings.fontColor).eq("red");
+        expect(data.app.settings.fontSize).eq("40");
+    });
+
+    it("should access property of JSON object content-type with data accessor", async () => {
+        const connectionString = createMockedConnectionString();
+        const settings = await load(connectionString, {
+            selectors: [{
+                keyFilter: "app2.*"
+            }]
+        });
+        expect(settings).not.undefined;
+        const data = settings.constructConfigurationObject();
+        expect(data).not.undefined;
+        expect(data.app2.settings.fontColor).eq("blue");
+        expect(data.app2.settings.fontSize).eq(20);
+    });
+
+    it("should not access property of JSON content-type object with get()", async () => {
+        const connectionString = createMockedConnectionString();
+        const settings = await load(connectionString, {
+            selectors: [{
+                keyFilter: "app2.*"
+            }]
+        });
+        expect(settings).not.undefined;
+        expect(settings.get("app2.settings")).not.undefined; // JSON object accessed as a whole
+        expect(settings.get("app2.settings.fontColor")).undefined;
+        expect(settings.get("app2.settings.fontSize")).undefined;
+    });
+
+    /**
+     * Edge case: Hierarchical key-value pairs with overlapped key prefix.
+     * key: "app3.settings" => value: "placeholder"
+     * key: "app3.settings.fontColor" => value: "yellow"
+     *
+     * get() will return "placeholder" for "app3.settings" and "yellow" for "app3.settings.fontColor", as expected.
+     * data.app3.settings will return "placeholder" as a whole JSON object, which is not guarenteed to be correct.
+     */
+    it("Edge case: Hierarchical key-value pairs with overlapped key prefix.", async () => {
+        const connectionString = createMockedConnectionString();
+        const settings = await load(connectionString, {
+            selectors: [{
+                keyFilter: "app3.settings*"
+            }]
+        });
+        expect(settings).not.undefined;
+        expect(() => {
+            settings.constructConfigurationObject();
+        }).to.throw("The key 'app3.settings' is not a valid path.");
+    });
+
+    it("should construct configuration object with array", async () => {
+        const connectionString = createMockedConnectionString();
+        const settings = await load(connectionString, {
+            selectors: [{
+                keyFilter: "app4.*"
+            }]
+        });
+        expect(settings).not.undefined;
+        const data = settings.constructConfigurationObject();
+        expect(data).not.undefined;
+        // Both { '0': 'node_modules', '1': 'dist' } and ['node_modules', 'dist'] are valid.
+        expect(data.app4.excludedFolders[0]).eq("node_modules");
+        expect(data.app4.excludedFolders[1]).eq("dist");
+    });
 });