Fix always firing onConfigChanged hook (#87)

* Fix always firing onConfigChanged hook

* Update ConfigServiceBase.ts

* Add test

* Bump version

package.json

@@ -1,6 +1,6 @@
 {
   "name": "configcat-common",
-  "version": "8.0.1",
+  "version": "8.0.2",
   "description": "ConfigCat is a configuration as a service that lets you manage your features and configurations without actually deploying new code.",
   "main": "lib/index.js",
   "types": "lib/index.d.ts",

src/ConfigServiceBase.ts

@@ -99,16 +99,15 @@ export abstract class ConfigServiceBase<TOptions extends OptionsBase> {
     const success = fetchResult.status === FetchStatus.Fetched;
     if (success
         || fetchResult.config.timestamp > latestConfig.timestamp && (!fetchResult.config.isEmpty || latestConfig.isEmpty)) {
+      await this.options.cache.set(this.cacheKey, fetchResult.config);
 
-      latestConfig = fetchResult.config;
-
-      await this.options.cache.set(this.cacheKey, latestConfig);
-
-      this.onConfigUpdated(latestConfig);
+      this.onConfigUpdated(fetchResult.config);
 
-      if (success) {
-        this.onConfigChanged(latestConfig);
+      if (success && (fetchResult.config.httpETag != latestConfig.httpETag || fetchResult.config.configJson != latestConfig.configJson)) {
+        this.onConfigChanged(fetchResult.config);
       }
+
+      latestConfig = fetchResult.config;
     }
 
     return [fetchResult, latestConfig];

test/ConfigCatClientTests.ts

@@ -496,6 +496,24 @@ describe("ConfigCatClient", () => {
     assert.equal(configChangedEventCount, 3);
   });
 
+  it("Initialization With AutoPollOptions - config doesn't change - should fire configChanged only once", async () => {
+
+    const configCatKernel: FakeConfigCatKernel = { configFetcher: new FakeConfigFetcher(), sdkType: "common", sdkVersion: "1.0.0" };
+    let configChangedEventCount = 0;
+    const pollIntervalSeconds = 1;
+    const userOptions: IAutoPollOptions = {
+      logger: null,
+      pollIntervalSeconds,
+      setupHooks: hooks => hooks.on("configChanged", () => configChangedEventCount++)
+    };
+    const options: AutoPollOptions = new AutoPollOptions("APIKEY", "common", "1.0.0", userOptions, null);
+    new ConfigCatClient(options, configCatKernel);
+
+    await delay(2.5 * pollIntervalSeconds * 1000);
+
+    assert.equal(configChangedEventCount, 1);
+  });
+
   it("Initialization With AutoPollOptions - with maxInitWaitTimeSeconds - getValueAsync should wait", async () => {
 
     const maxInitWaitTimeSeconds = 2;