Refactor AzureAppConfiguration with new interfaces

Author: Eskibear

src/AzureAppConfiguration.ts

@@ -16,4 +16,12 @@ export type AzureAppConfiguration = {
      * @param thisArg - Optional. Value to use as `this` when executing callback.
      */
     onRefresh(listener: () => any, thisArg?: any): Disposable;
-} & ReadonlyMap<string, any>;
+} & IGettable & AppConfigurationData;
+
+interface AppConfigurationData {
+    data: { [key: string]: any };
+}
+
+interface IGettable {
+    get<T>(key: string): T | undefined;
+}

src/AzureAppConfigurationImpl.ts

@@ -15,7 +15,22 @@ 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 {
+    /**
+     * App Configuration data
+     */
+    readonly data: { [key: string]: any } = {};
+
+    /**
+     * Separator for hierarchical keys.
+     */
+    readonly #SEP: string = ".";
+
+    /**
+     * 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 +55,6 @@ export class AzureAppConfigurationImpl extends Map<string, any> implements Azure
         client: AppConfigurationClient,
         options: AzureAppConfigurationOptions | undefined
     ) {
-        super();
         this.#client = client;
         this.#options = options;
 
@@ -87,6 +101,9 @@ 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;
@@ -157,22 +174,51 @@ 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);
         }
+        // also construct hierarchical data object from map
+        this.#constructDataFromMap();
     }
 
     /**
      * Load the configuration store for the first time.
      */
     async load() {
         await this.#loadSelectedAndWatchedKeyValues();
-
         // Mark all settings have loaded at startup.
         this.#isInitialLoadCompleted = true;
     }
 
+    /**
+     * Construct hierarchical data object from map.
+     *
+     * @remarks
+     * This method is used to construct hierarchical data object from map, and it is called after the initial load and each refresh.
+     */
+    #constructDataFromMap() {
+        // clean data object in-place
+        for (const key of Object.keys(this.data)) {
+            delete this.data[key];
+        }
+        // construct hierarchical data object from map
+        for (const [key, value] of this.#configMap) {
+            const segments = key.split(this.#SEP);
+            let current = this.data;
+            // construct hierarchical data object along the path
+            for (let i = 0; i < segments.length - 1; i++) {
+                const segment = segments[i];
+                if (typeof current[segment] !== "object") { // Note: it overwrites existing value if it's not an object
+                    current[segment] = {};
+                }
+                current = current[segment];
+            }
+            // set value to the last segment
+            current[segments[segments.length - 1]] = value;
+        }
+    }
+
     /**
      * 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

@@ -28,6 +28,16 @@ const mockedKVs = [{
 }, {
     key: "KeyForEmptyValue",
     value: "",
+}, {
+    key: "app2.settings",
+    value: JSON.stringify({ fontColor: "blue", fontSize: 20 }),
+    contentType: "application/json"
+}, {
+    key: "app3.settings",
+    value: "placeholder"
+}, {
+    key: "app3.settings.fontColor",
+    value: "yellow"
 }].map(createMockedKeyValue);
 
 describe("load", function () {
@@ -83,11 +93,8 @@ 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 () => {
@@ -100,20 +107,15 @@ 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("");
     });
 
@@ -148,7 +150,6 @@ describe("load", function () {
             }]
         });
         expect(settings).not.undefined;
-        expect(settings.has("TestKey")).eq(true);
         expect(settings.get("TestKey")).eq("TestValueForProd");
     });
 
@@ -167,8 +168,54 @@ 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);
+        expect(settings).not.undefined;
+        expect(settings.data).not.undefined;
+        expect(settings.data.app.settings.fontColor).eq("red");
+        expect(settings.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);
+        expect(settings).not.undefined;
+        expect(settings.data).not.undefined;
+        expect(settings.data.app2.settings.fontColor).eq("blue");
+        expect(settings.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);
+        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);
+        expect(settings).not.undefined;
+        // use get() method
+        expect(settings.get("app3.settings")).eq("placeholder");
+        expect(settings.get("app3.settings.fontColor")).eq("yellow");
+        // use data property
+        expect(settings.data.app3.settings).not.eq("placeholder"); // not as expected.
+        expect(settings.data.app3.settings.fontColor).eq("yellow");
+    });
 });