Use local storage to serve gate requests while init pending (#102)

* Use local storage to serve gate requests while the network request is pending
statsig-io · Oct 19, 2021 · 88dad64 · 88dad64
1 parent b177efd
commit 88dad64
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Showing 4 changed files with 147 additions and 11 deletions.
diff --git a/package.json b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "statsig-js",
-  "version": "4.4.0-beta.1",
+  "version": "4.4.0",
   "description": "Statsig JavaScript client SDK for single user environments.",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",

diff --git a/src/StatsigClient.ts b/src/StatsigClient.ts
@@ -198,9 +198,7 @@ export default class StatsigClient implements IHasStatsigInternal, IStatsig {
    * @throws Error if initialize() is not called first, or gateName is not a string
    */
   public checkGate(gateName: string): boolean {
-    if (!this.ready) {
-      throw new Error('Call and wait for initialize() to finish first.');
-    }
+    this.ensureStoreLoaded();
     if (typeof gateName !== 'string' || gateName.length === 0) {
       throw new Error('Must pass a valid string as the gateName.');
     }
@@ -214,9 +212,7 @@ export default class StatsigClient implements IHasStatsigInternal, IStatsig {
    * @throws Error if initialize() is not called first, or configName is not a string
    */
   public getConfig(configName: string): DynamicConfig {
-    if (!this.ready) {
-      throw new Error('Call and wait for initialize() to finish first.');
-    }
+    this.ensureStoreLoaded();
     if (typeof configName !== 'string' || configName.length === 0) {
       throw new Error('Must pass a valid string as the configName.');
     }
@@ -234,9 +230,7 @@ export default class StatsigClient implements IHasStatsigInternal, IStatsig {
     experimentName: string,
     keepDeviceValue: boolean = false,
   ): DynamicConfig {
-    if (!this.ready) {
-      throw new Error('Call and wait for initialize() to finish first.');
-    }
+    this.ensureStoreLoaded();
     if (typeof experimentName !== 'string' || experimentName.length === 0) {
       throw new Error('Must pass a valid string as the experimentName.');
     }
@@ -326,6 +320,7 @@ export default class StatsigClient implements IHasStatsigInternal, IStatsig {
    * @param value the value to override the gate to
    */
   public overrideGate(gateName: string, value: boolean): void {
+    this.ensureStoreLoaded();
     this.store.overrideGate(gateName, value);
   }
 
@@ -335,6 +330,7 @@ export default class StatsigClient implements IHasStatsigInternal, IStatsig {
    * @param value the json value to override the config to
    */
   public overrideConfig(configName: string, value: Record<string, any>): void {
+    this.ensureStoreLoaded();
     this.store.overrideConfig(configName, value);
   }
 
@@ -343,6 +339,7 @@ export default class StatsigClient implements IHasStatsigInternal, IStatsig {
    * @param gateName
    */
   public removeGateOverride(gateName?: string): void {
+    this.ensureStoreLoaded();
     this.store.removeGateOverride(gateName);
   }
 
@@ -351,6 +348,7 @@ export default class StatsigClient implements IHasStatsigInternal, IStatsig {
    * @param configName
    */
   public removeConfigOverride(configName?: string): void {
+    this.ensureStoreLoaded();
     this.store.removeConfigOverride(configName);
   }
 
@@ -360,6 +358,7 @@ export default class StatsigClient implements IHasStatsigInternal, IStatsig {
    * @param gateName
    */
   public removeOverride(gateName?: string): void {
+    this.ensureStoreLoaded();
     this.store.removeGateOverride(gateName);
   }
 
@@ -368,13 +367,15 @@ export default class StatsigClient implements IHasStatsigInternal, IStatsig {
    * @returns Gate overrides
    */
   public getOverrides(): Record<string, any> {
+    this.ensureStoreLoaded();
     return this.store.getAllOverrides().gates;
   }
 
   /**
    * @returns The local gate and config overrides
    */
   public getAllOverrides(): StatsigOverrides {
+    this.ensureStoreLoaded();
     return this.store.getAllOverrides();
   }
 
@@ -482,4 +483,10 @@ export default class StatsigClient implements IHasStatsigInternal, IStatsig {
     }
     return user;
   }
+
+  private ensureStoreLoaded(): void {
+    if (!this.store.isLoaded()) {
+      throw new Error('Call and wait for initialize() to finish first.');
+    }
+  }
 }
diff --git a/src/StatsigStore.ts b/src/StatsigStore.ts
@@ -53,6 +53,7 @@ export default class StatsigStore {
     configs: {},
   };
 
+  private loaded: boolean;
   private values: APIInitializeData;
   private stickyUserExperiments: StickyUserExperiments;
   private stickyDeviceExperiments: Record<string, APIDynamicConfig>;
@@ -65,6 +66,7 @@ export default class StatsigStore {
       experiments: {},
     };
     this.stickyDeviceExperiments = {};
+    this.loaded = false;
   }
 
   public async loadFromAsyncStorage(): Promise<void> {
@@ -73,6 +75,7 @@ export default class StatsigStore {
       await StatsigAsyncStorage.getItemAsync(STICKY_USER_EXPERIMENTS_KEY),
       await StatsigAsyncStorage.getItemAsync(STICKY_DEVICE_EXPERIMENTS_KEY),
     );
+    this.loaded = true;
   }
 
   public loadFromLocalStorage(): void {
@@ -81,6 +84,11 @@ export default class StatsigStore {
       StatsigLocalStorage.getItem(STICKY_USER_EXPERIMENTS_KEY),
       StatsigLocalStorage.getItem(STICKY_DEVICE_EXPERIMENTS_KEY),
     );
+    this.loaded = true;
+  }
+
+  public isLoaded(): boolean {
+    return this.loaded;
   }
 
   private parseCachedValues(
@@ -148,7 +156,6 @@ export default class StatsigStore {
 
   public async save(jsonConfigs: Record<string, any>): Promise<void> {
     this.values = jsonConfigs as APIInitializeData;
-
     if (StatsigAsyncStorage.asyncStorage) {
       await StatsigAsyncStorage.setItemAsync(
         INTERNAL_STORE_KEY,

diff --git a/src/__tests__/StatsigClientCache.test.ts b/src/__tests__/StatsigClientCache.test.ts
@@ -0,0 +1,122 @@
+/**
+ * @jest-environment jsdom
+ */
+
+import StatsigClient from '../StatsigClient';
+import StatsigAsyncStorage from '../utils/StatsigAsyncLocalStorage';
+import StatsigStore from '../StatsigStore';
+describe('Verify behavior of StatsigClient', () => {
+  const sdkKey = 'client-clienttestkey';
+  jest.useFakeTimers();
+
+  class LocalStorageMock {
+    private store: Record<string, string>;
+    constructor() {
+      this.store = {
+        STATSIG_LOCAL_STORAGE_INTERNAL_STORE_V3: JSON.stringify({
+          feature_gates: {
+            'AoZS0F06Ub+W2ONx+94rPTS7MRxuxa+GnXro5Q1uaGY=': {
+              value: true,
+              rule_id: 'cache',
+            },
+          },
+          dynamic_configs: {
+            'RMv0YJlLOBe7cY7HgZ3Jox34R0Wrk7jLv3DZyBETA7I=': {
+              value: {
+                param: 'cache',
+              },
+              rule_id: 'cache',
+            },
+          },
+        }),
+      };
+    }
+
+    clear() {
+      this.store = {};
+    }
+
+    getItem(key: string) {
+      return this.store[key] || null;
+    }
+
+    setItem(key: string, value: string) {
+      this.store[key] = String(value);
+    }
+
+    removeItem(key: string) {
+      delete this.store[key];
+    }
+  }
+  const localStorage = new LocalStorageMock();
+  // @ts-ignore
+  Object.defineProperty(window, 'localStorage', {
+    value: localStorage,
+  });
+
+  // @ts-ignore
+  global.fetch = jest.fn(() => {
+    return new Promise((resolve) => {
+      setTimeout(() => {
+        // @ts-ignore
+        resolve({
+          ok: true,
+          json: () =>
+            Promise.resolve({
+              feature_gates: {
+                'AoZS0F06Ub+W2ONx+94rPTS7MRxuxa+GnXro5Q1uaGY=': {
+                  value: false,
+                  rule_id: 'network',
+                },
+              },
+              dynamic_configs: {
+                'RMv0YJlLOBe7cY7HgZ3Jox34R0Wrk7jLv3DZyBETA7I=': {
+                  value: {
+                    param: 'network',
+                  },
+                  rule_id: 'network',
+                },
+              },
+            }),
+        });
+      }, 1000);
+    });
+  });
+
+  test('Test constructor', () => {
+    expect.assertions(4);
+    const client = new StatsigClient();
+    expect(() => {
+      client.checkGate('gate');
+    }).toThrowError('Call and wait for initialize() to finish first.');
+    expect(() => {
+      client.getConfig('config');
+    }).toThrowError('Call and wait for initialize() to finish first.');
+    expect(() => {
+      client.getExperiment('experiment');
+    }).toThrowError('Call and wait for initialize() to finish first.');
+    expect(() => {
+      client.logEvent('event');
+    }).toThrowError('Must initialize() before logging events.');
+  });
+
+  test('cache used before initialize resolves, then network result used', async () => {
+    expect.assertions(4);
+    const statsig = new StatsigClient();
+    const init = statsig.initializeAsync(sdkKey, { userID: '123' });
+
+    // test_gate is true from the cache
+    expect(statsig.checkGate('test_gate')).toBe(true);
+    expect(
+      statsig.getConfig('test_config').get<string>('param', 'default'),
+    ).toEqual('cache');
+
+    jest.advanceTimersByTime(2000);
+    await init;
+
+    expect(statsig.checkGate('test_gate')).toBe(false);
+    expect(
+      statsig.getConfig('test_config').get<string>('param', 'default'),
+    ).toEqual('network');
+  });
+});