feat(utils): kill unused promise buffer api (#4330)

Author: mitsuhiko

packages/utils/src/promisebuffer.ts

@@ -23,9 +23,10 @@ function allPromises<U = unknown>(collection: Array<U | PromiseLike<U>>): Promis
 }
 
 export interface PromiseBuffer<T> {
-  length(): number;
+  // exposes the internal array so tests can assert on the state of it.
+  // XXX: this really should not be public api.
+  $: Array<PromiseLike<T>>;
   add(taskProducer: () => PromiseLike<T>): PromiseLike<T>;
-  remove(task: PromiseLike<T>): PromiseLike<T>;
   drain(timeout?: number): PromiseLike<boolean>;
 }
 
@@ -36,10 +37,6 @@ export interface PromiseBuffer<T> {
 export function makePromiseBuffer<T>(limit?: number): PromiseBuffer<T> {
   const buffer: Array<PromiseLike<T>> = [];
 
-  function length(): number {
-    return buffer.length;
-  }
-
   function isReady(): boolean {
     return limit === undefined || buffer.length < limit;
   }
@@ -113,12 +110,9 @@ export function makePromiseBuffer<T>(limit?: number): PromiseBuffer<T> {
     });
   }
 
-  const promiseBuffer: PromiseBuffer<T> = {
-    length,
+  return {
+    $: buffer,
     add,
-    remove,
     drain,
   };
-
-  return promiseBuffer;
 }

packages/utils/test/promisebuffer.test.ts

@@ -7,7 +7,7 @@ describe('PromiseBuffer', () => {
       const buffer = makePromiseBuffer();
       const p = jest.fn(() => new SyncPromise(resolve => setTimeout(resolve)));
       void buffer.add(p);
-      expect(buffer.length()).toEqual(1);
+      expect(buffer.$.length).toEqual(1);
     });
 
     test('with limit', () => {
@@ -20,7 +20,7 @@ describe('PromiseBuffer', () => {
       const producer2 = jest.fn(() => new SyncPromise(resolve => setTimeout(resolve)));
       expect(buffer.add(producer1)).toEqual(task1);
       void expect(buffer.add(producer2)).rejects.toThrowError();
-      expect(buffer.length()).toEqual(1);
+      expect(buffer.$.length).toEqual(1);
       expect(producer1).toHaveBeenCalled();
       expect(producer2).not.toHaveBeenCalled();
     });
@@ -32,51 +32,51 @@ describe('PromiseBuffer', () => {
       for (let i = 0; i < 5; i++) {
         void buffer.add(() => new SyncPromise(resolve => setTimeout(resolve)));
       }
-      expect(buffer.length()).toEqual(5);
+      expect(buffer.$.length).toEqual(5);
       const result = await buffer.drain();
       expect(result).toEqual(true);
-      expect(buffer.length()).toEqual(0);
+      expect(buffer.$.length).toEqual(0);
     });
 
     test('with timeout', async () => {
       const buffer = makePromiseBuffer();
       for (let i = 0; i < 5; i++) {
         void buffer.add(() => new SyncPromise(resolve => setTimeout(resolve, 100)));
       }
-      expect(buffer.length()).toEqual(5);
+      expect(buffer.$.length).toEqual(5);
       const result = await buffer.drain(50);
       expect(result).toEqual(false);
     });
 
     test('on empty buffer', async () => {
       const buffer = makePromiseBuffer();
-      expect(buffer.length()).toEqual(0);
+      expect(buffer.$.length).toEqual(0);
       const result = await buffer.drain();
       expect(result).toEqual(true);
-      expect(buffer.length()).toEqual(0);
+      expect(buffer.$.length).toEqual(0);
     });
   });
 
   test('resolved promises should not show up in buffer length', async () => {
     const buffer = makePromiseBuffer();
     const producer = () => new SyncPromise(resolve => setTimeout(resolve));
     const task = buffer.add(producer);
-    expect(buffer.length()).toEqual(1);
+    expect(buffer.$.length).toEqual(1);
     await task;
-    expect(buffer.length()).toEqual(0);
+    expect(buffer.$.length).toEqual(0);
   });
 
   test('rejected promises should not show up in buffer length', async () => {
     const buffer = makePromiseBuffer();
     const producer = () => new SyncPromise((_, reject) => setTimeout(reject));
     const task = buffer.add(producer);
-    expect(buffer.length()).toEqual(1);
+    expect(buffer.$.length).toEqual(1);
     try {
       await task;
     } catch (_) {
       // no-empty
     }
-    expect(buffer.length()).toEqual(0);
+    expect(buffer.$.length).toEqual(0);
   });
 
   test('resolved task should give an access to the return value', async () => {