Merge pull request #15802 from strapi/feature/async-reduce-utils

feat(utils): add ReduceAsync function

docs/docs/core/utils/async.md

@@ -16,6 +16,7 @@ Available functions:
 
 - pipeAsync
 - mapAsync
+- reduceAsync
 
 [See API reference](../../api/Utils) (TODO)
 

packages/core/utils/lib/__tests__/async.test.js

@@ -1,6 +1,6 @@
 'use strict';
 
-const { pipeAsync, mapAsync } = require('../async');
+const { pipeAsync, mapAsync, reduceAsync } = require('../async');
 
 describe('Async utils', () => {
   describe('pipeAsync', () => {
@@ -77,4 +77,58 @@ describe('Async utils', () => {
       expect(maxOperations).toEqual(2);
     });
   });
+  describe('reduceAsync', () => {
+    test('Should return an incremented number', async () => {
+      const numberPromiseArray = [Promise.resolve(1), Promise.resolve(2)];
+
+      const reduceFunc = reduceAsync(numberPromiseArray);
+      const result = await reduceFunc(
+        (previousValue, currentValue) => previousValue + currentValue,
+        10
+      );
+
+      expect(result).toEqual(13);
+    });
+    test('Should work without initial value', async () => {
+      const numberPromiseArray = [Promise.resolve(1), Promise.resolve(2)];
+
+      const reduceFunc = reduceAsync(numberPromiseArray);
+      const result = await reduceFunc(
+        (previousValue, currentValue) => (previousValue || 10) + currentValue
+      );
+
+      expect(result).toEqual(13);
+    });
+    test('Should work with mix of promises and values', async () => {
+      const numberMixArray = [1, Promise.resolve(2)];
+
+      const reduceFunc = reduceAsync(numberMixArray);
+      const result = await reduceFunc(
+        (previousValue, currentValue) => previousValue + currentValue,
+        10
+      );
+
+      expect(result).toEqual(13);
+    });
+    test('Should throw an error with proper message when the provided callback throws an error', async () => {
+      const numberPromiseArray = [Promise.resolve(1), Promise.resolve(2)];
+
+      const reduceFunc = reduceAsync(numberPromiseArray);
+
+      await expect(async () => {
+        await reduceFunc(() => {
+          throw new Error('test');
+        });
+      }).rejects.toThrow('test');
+    });
+    test('Should throw an error with proper message when the input array contains a rejected Promise', async () => {
+      const numberPromiseArray = [Promise.reject(new Error('input')), Promise.resolve(2)];
+
+      const reduceFunc = reduceAsync(numberPromiseArray);
+
+      await expect(async () => {
+        await reduceFunc(() => true, null);
+      }).rejects.toThrow('input');
+    });
+  });
 });

packages/core/utils/lib/async.d.ts

@@ -1,4 +1,6 @@
-export type MapAsync<T = any, R = any> = lodash.CurriedFunction3<
+import { CurriedFunction3 } from 'lodash';
+
+export type MapAsync<T = any, R = any> = CurriedFunction3<
   T[],
   (element: T, index: number) => R | Promise<R>,
   { concurrency?: number },
@@ -10,3 +12,10 @@ export type ForEachAsync<T = any, R = any> = (
   func: (element: T, index: number) => R | Promise<R>,
   options?: { concurrency?: number }
 ) => Promise<R[]>;
+
+export type ReduceAsync<T = any, V = T, R = V> = CurriedFunction3<
+  T[],
+  (accumulator: V | R, current: Awaited<T>, index: number) => R | Promise<R>,
+  V,
+  Promise<R>
+>;

packages/core/utils/lib/async.js

@@ -1,7 +1,7 @@
 'use strict';
 
 const pMap = require('p-map');
-const { curry } = require('lodash/fp');
+const { curry, curryN } = require('lodash/fp');
 
 function pipeAsync(...methods) {
   return async (data) => {
@@ -20,6 +20,17 @@ function pipeAsync(...methods) {
  */
 const mapAsync = curry(pMap);
 
+/**
+ * @type { import('./async').ReduceAsync }
+ */
+const reduceAsync = curryN(2, async (mixedArray, iteratee, initialValue) => {
+  let acc = initialValue;
+  for (let i = 0; i < mixedArray.length; i += 1) {
+    acc = await iteratee(acc, await mixedArray[i], i);
+  }
+  return acc;
+});
+
 /**
  * @type { import('./async').ForEachAsync }
  */
@@ -29,6 +40,7 @@ const forEachAsync = curry(async (array, func, options) => {
 
 module.exports = {
   mapAsync,
+  reduceAsync,
   forEachAsync,
   pipeAsync,
 };

packages/core/utils/lib/index.js

@@ -37,7 +37,7 @@ const providerFactory = require('./provider-factory');
 const pagination = require('./pagination');
 const sanitize = require('./sanitize');
 const traverseEntity = require('./traverse-entity');
-const { pipeAsync, mapAsync, forEachAsync } = require('./async');
+const { pipeAsync, mapAsync, reduceAsync, forEachAsync } = require('./async');
 const convertQueryParams = require('./convert-query-params');
 const importDefault = require('./import-default');
 const template = require('./template');
@@ -83,6 +83,7 @@ module.exports = {
   pagination,
   pipeAsync,
   mapAsync,
+  reduceAsync,
   forEachAsync,
   errors,
   validateYupSchema,