update pre-init buffer, add tests

Author: silesky

src/__tests__/analytics-pre-init.integration.test.ts

@@ -318,7 +318,7 @@ describe('Pre-initialization', () => {
       expect(onIdentifyCb).toHaveBeenCalledWith('bar', {}, undefined)
     })
 
-    test('the "this" value of event callbacks should be Analytics', async () => {
+    test('the "this" value of "emitted" event callbacks should be Analytics', async () => {
       const ajsBuffered = AnalyticsBrowser.load({ writeKey })
       ajsBuffered.on('track', function onTrackCb(this: any) {
         expect(this).toBeInstanceOf(Analytics)

src/__tests__/analytics-pre-init.test.ts

@@ -9,6 +9,40 @@ import { Analytics } from '../analytics'
 import { Context } from '../core/context'
 import { sleep } from './test-helpers/sleep'
 
+describe('PreInitMethodCallBuffer', () => {
+  describe('push', () => {
+    it('should return this', async () => {
+      const buffer = new PreInitMethodCallBuffer()
+      const result = buffer.push({} as any)
+      expect(result).toBeInstanceOf(PreInitMethodCallBuffer)
+    })
+  })
+  describe('getCalls', () => {
+    it('should return calls', async () => {
+      const buffer = new PreInitMethodCallBuffer()
+
+      const fooCall1 = {
+        method: 'foo',
+        args: ['bar'],
+      } as any
+
+      const barCall = {
+        method: 'bar',
+        args: ['foobar'],
+      } as any
+
+      const fooCall2 = {
+        method: 'foo',
+        args: ['baz'],
+      } as any
+
+      const calls: PreInitMethodCall<any>[] = [fooCall1, fooCall2, barCall]
+      const result = buffer.push(...calls)
+      expect(result.getCalls('foo' as any)).toEqual([fooCall1, fooCall2])
+    })
+  })
+})
+
 describe('AnalyticsBuffered', () => {
   describe('Happy path', () => {
     it('should return a promise-like object', async () => {
@@ -177,7 +211,10 @@ describe('flushAnalyticsCallsInNewTask', () => {
       reject: jest.fn(),
     } as PreInitMethodCall<any>
 
-    const buffer = new PreInitMethodCallBuffer([synchronousMethod, asyncMethod])
+    const buffer = new PreInitMethodCallBuffer().push(
+      synchronousMethod,
+      asyncMethod
+    )
 
     flushAnalyticsCallsInNewTask(new Analytics({ writeKey: 'abc' }), buffer)
     expect(synchronousMethod.resolve).not.toBeCalled()
@@ -199,7 +236,7 @@ describe('flushAnalyticsCallsInNewTask', () => {
       reject: jest.fn(),
     } as PreInitMethodCall<any>
 
-    const buffer = new PreInitMethodCallBuffer([asyncMethod])
+    const buffer = new PreInitMethodCallBuffer().push(asyncMethod)
     flushAnalyticsCallsInNewTask(new Analytics({ writeKey: 'abc' }), buffer)
     await sleep(0)
     expect(asyncMethod.reject).toBeCalledWith('oops!')
@@ -230,7 +267,10 @@ describe('flushAnalyticsCallsInNewTask', () => {
       reject: jest.fn(),
     } as PreInitMethodCall<any>
 
-    const buffer = new PreInitMethodCallBuffer([synchronousMethod, asyncMethod])
+    const buffer = new PreInitMethodCallBuffer().push(
+      synchronousMethod,
+      asyncMethod
+    )
     flushAnalyticsCallsInNewTask(new Analytics({ writeKey: 'abc' }), buffer)
     await sleep(0)
     expect(synchronousMethod.reject).toBeCalled()

src/analytics-pre-init.ts

@@ -141,12 +141,6 @@ type MethodCallMap = Partial<Record<PreInitMethodName, PreInitMethodCall[]>>
  *  Represents any and all the buffered method calls that occurred before initialization.
  */
 export class PreInitMethodCallBuffer {
-  constructor(calls?: PreInitMethodCall[]) {
-    if (calls) {
-      this.push(...calls)
-    }
-  }
-
   private _value = {} as MethodCallMap
 
   public toArray(): PreInitMethodCall[] {
@@ -161,18 +155,20 @@ export class PreInitMethodCallBuffer {
     return (this._value[methodName] ?? []) as PreInitMethodCall<T>[]
   }
 
-  push(...calls: PreInitMethodCall[]): void {
+  push(...calls: PreInitMethodCall[]): PreInitMethodCallBuffer {
     calls.forEach((el) => {
       if (this._value[el.method]) {
         this._value[el.method]?.push(el)
       } else {
         this._value[el.method] = [el]
       }
     })
+    return this
   }
 
-  clear(): void {
+  clear(): PreInitMethodCallBuffer {
     this._value = {} as MethodCallMap
+    return this
   }
 }