Split utils into multiple files

Author: wojtekmaj

src/forEach.js

@@ -0,0 +1,5 @@
+import asyncMap from './map';
+
+export default async function asyncForEach(arr, fn) {
+  await asyncMap(arr, fn);
+}

src/forEach.spec.js

@@ -0,0 +1,55 @@
+import asyncForEach from './forEach';
+
+import {
+  inputArr,
+  makePushDuplicate,
+  makePushDuplicateInRandomTime,
+} from '../test-utils';
+
+describe('asyncForEach()', () => {
+  it.skip('assertions below are valid for synchronous .forEach()', () => {
+    const [arr, pushDuplicate] = makePushDuplicate();
+    const mapper = jest.fn().mockImplementation(pushDuplicate);
+
+    inputArr.forEach(mapper);
+
+    expect.assertions(1 + inputArr.length);
+
+    expect(mapper).toHaveBeenCalledTimes(inputArr.length);
+    inputArr.forEach((el) => {
+      expect(arr).toContain(el * 2);
+    });
+  });
+
+  it('iterates through an array properly', async () => {
+    const [arr, pushDuplicate] = makePushDuplicateInRandomTime();
+    const mapper = jest.fn().mockImplementation(pushDuplicate);
+
+    await asyncForEach(inputArr, mapper);
+
+    expect.assertions(1 + inputArr.length);
+
+    expect(mapper).toHaveBeenCalledTimes(inputArr.length);
+    inputArr.forEach((el) => {
+      expect(arr).toContain(el * 2);
+    });
+  });
+
+  it.skip('assertions below are valid for synchronous .forEach()', () => {
+    const [, pushDuplicate] = makePushDuplicate();
+    const mapper = jest.fn().mockImplementation(pushDuplicate);
+
+    const result = inputArr.forEach(mapper);
+
+    expect(result).toBe(undefined);
+  });
+
+  it('returns undefined', async () => {
+    const [, pushDuplicate] = makePushDuplicate();
+    const mapper = jest.fn().mockImplementation(pushDuplicate);
+
+    const result = await asyncForEach(inputArr, mapper);
+
+    expect(result).toBe(undefined);
+  });
+});

src/forEach_strict.js

@@ -0,0 +1,5 @@
+import asyncMapStrict from './map_strict';
+
+export default async function asyncForEachStrict(arr, fn) {
+  await asyncMapStrict(arr, fn);
+}

src/forEach_strict.spec.js

@@ -0,0 +1,75 @@
+import asyncForEachStrict from './forEach_strict';
+import {
+  doubleInputArr,
+  inputArr,
+  makePushDuplicate,
+  makePushDuplicateInRandomTime,
+} from '../test-utils';
+
+describe('asyncForEachStrict()', () => {
+  it.skip('assertions below are valid for synchronous .forEach()', () => {
+    const [arr, pushDuplicate] = makePushDuplicate();
+    const mapper = jest.fn().mockImplementation(pushDuplicate);
+
+    inputArr.forEach(mapper);
+
+    expect.assertions(1 + inputArr.length);
+
+    expect(mapper).toHaveBeenCalledTimes(inputArr.length);
+    inputArr.forEach((el) => {
+      expect(arr).toContain(el * 2);
+    });
+  });
+
+  it('iterates through an array properly', async () => {
+    const [arr, pushDuplicate] = makePushDuplicateInRandomTime();
+    const mapper = jest.fn().mockImplementation(pushDuplicate);
+
+    await asyncForEachStrict(inputArr, mapper);
+
+    expect.assertions(1 + inputArr.length);
+
+    expect(mapper).toHaveBeenCalledTimes(inputArr.length);
+    inputArr.forEach((el) => {
+      expect(arr).toContain(el * 2);
+    });
+  });
+
+  it.skip('assertions below are valid for synchronous .forEach()', () => {
+    const [arr, pushDuplicate] = makePushDuplicate();
+    const mapper = jest.fn().mockImplementation(pushDuplicate);
+
+    inputArr.forEach(mapper);
+
+    expect(mapper).toHaveBeenCalledTimes(inputArr.length);
+    expect(arr).toEqual(doubleInputArr);
+  });
+
+  it('iterates through an array properly with side effects', async () => {
+    const [arr, pushDuplicate] = makePushDuplicateInRandomTime();
+    const mapper = jest.fn().mockImplementation(pushDuplicate);
+
+    await asyncForEachStrict(inputArr, mapper);
+
+    expect(mapper).toHaveBeenCalledTimes(inputArr.length);
+    expect(arr).toEqual(doubleInputArr);
+  });
+
+  it.skip('assertions below are valid for synchronous .forEach()', () => {
+    const [, pushDuplicate] = makePushDuplicate();
+    const mapper = jest.fn().mockImplementation(pushDuplicate);
+
+    const result = inputArr.forEach(mapper);
+
+    expect(result).toBe(undefined);
+  });
+
+  it('returns undefined', async () => {
+    const [, pushDuplicate] = makePushDuplicate();
+    const mapper = jest.fn().mockImplementation(pushDuplicate);
+
+    const result = await asyncForEachStrict(inputArr, mapper);
+
+    expect(result).toBe(undefined);
+  });
+});

src/index.js

@@ -1,37 +1,13 @@
-export async function asyncMap(arr, fn) {
-  return Promise.all(arr.map(fn));
-}
-
-export async function asyncMapStrict(arr, fn) {
-  const result = [];
-
-  for (let idx = 0; idx < arr.length; idx += 1) {
-    const cur = arr[idx];
-
-    // eslint-disable-next-line no-await-in-loop
-    result.push(await fn(cur, idx, arr));
-  }
-
-  return result;
-}
-
-export async function asyncForEach(arr, fn) {
-  await asyncMap(arr, fn);
-}
-
-export async function asyncForEachStrict(arr, fn) {
-  await asyncMapStrict(arr, fn);
-}
-
-export async function asyncReduce(arr, fn, initialValue) {
-  let temp = initialValue;
-
-  for (let idx = 0; idx < arr.length; idx += 1) {
-    const cur = arr[idx];
-
-    // eslint-disable-next-line no-await-in-loop
-    temp = await fn(temp, cur, idx);
-  }
-
-  return temp;
-}
+import asyncForEach from './forEach';
+import asyncForEachStrict from './forEach_strict';
+import asyncMap from './map';
+import asyncMapStrict from './map_strict';
+import asyncReduce from './reduce';
+
+export {
+  asyncForEach,
+  asyncForEachStrict,
+  asyncMap,
+  asyncMapStrict,
+  asyncReduce,
+};