Require Node.js 12.20 and move to ESM

.github/workflows/main.yml

@@ -10,13 +10,10 @@ jobs:
       fail-fast: false
       matrix:
         node-version:
-          - 14
-          - 12
-          - 10
-          - 8
+          - 16
     steps:
       - uses: actions/checkout@v2
-      - uses: actions/setup-node@v1
+      - uses: actions/setup-node@v2
         with:
           node-version: ${{ matrix.node-version }}
       - run: npm install

index.d.ts

@@ -1,36 +1,21 @@
-declare const pSeries: {
-	/**
-	Run promise-returning & async functions in series.
+/**
+Run promise-returning & async functions in series.
 
-	@param tasks - Functions are expected to return a value. If a Promise is returned, it's awaited before continuing with the next task.
-	@returns A `Promise` that is fulfilled when all promises returned from calling the functions in `tasks` are fulfilled, or rejects if any of the promises reject. The fulfilled value is an `Array` of the fulfilled values.
+@param tasks - Functions are expected to return a value. If a Promise is returned, it's awaited before continuing with the next task.
+@returns A `Promise` that is fulfilled when all promises returned from calling the functions in `tasks` are fulfilled, or rejects if any of the promises reject. The fulfilled value is an `Array` of the fulfilled values.
 
-	@example
-	```
-	import pSeries = require('p-series');
-	import got = require('got');
+@example
+```
+import pSeries from 'p-series';
+import got from 'got';
 
-	(async () => {
-		const tasks = [
-			() => got('https://sindresorhus.com'),
-			() => checkSomething(),
-			() => doSomethingElse()
-		];
+const tasks = [
+	() => got('https://sindresorhus.com'),
+	() => checkSomething(),
+	() => doSomethingElse()
+];
 
-		console.log(await pSeries(tasks));
-	})();
-	```
-	*/
-	<ValueType>(tasks: Iterable<() => Promise<ValueType> | ValueType>): Promise<
-		ValueType[]
-	>;
-
-	// TODO: Remove this for the next major release, refactor the whole definition to:
-	// declare function pSeries<ValueType>(
-	// 	tasks: Iterable<() => Promise<ValueType> | ValueType>
-	// ): Promise<ValueType[]>;
-	// export = pSeries;
-	default: typeof pSeries;
-};
-
-export = pSeries;
+console.log(await pSeries(tasks));
+```
+*/
+export default function pSeries<ValueType>(tasks: Iterable<() => Promise<ValueType> | ValueType>): Promise<ValueType[]>;

index.js

@@ -1,26 +1,15 @@
-'use strict';
-const pReduce = require('p-reduce');
-const is = require('@sindresorhus/is');
+export default async function pSeries(tasks) {
+	for (const task of tasks) {
+		if (typeof task !== 'function') {
+			throw new TypeError(`Expected task to be a \`Function\`, received \`${typeof task}\``);
+		}
+	}
 
-const pSeries = async tasks => {
 	const results = [];
 
 	for (const task of tasks) {
-		const type = is(task);
-
-		if (type !== 'Function') {
-			throw new TypeError(`Expected task to be a \`Function\`, received \`${type}\``);
-		}
+		results.push(await task()); // eslint-disable-line no-await-in-loop
 	}
 
-	await pReduce(tasks, async (_, task) => {
-		const value = await task();
-		results.push(value);
-	});
-
 	return results;
-};
-
-module.exports = pSeries;
-// TODO: Remove this for the next major release
-module.exports.default = pSeries;
+}

index.test-d.ts

@@ -1,9 +1,9 @@
 import {expectType} from 'tsd';
-import pSeries = require('.');
+import pSeries from './index.js';
 
-expectType<Promise<(number | boolean)[]>>(
-	pSeries<number | boolean>([() => Promise.resolve(1), () => true])
+expectType<Promise<Array<number | boolean>>>(
+	pSeries<number | boolean>([async () => Promise.resolve(1), () => true]),
 );
-expectType<Promise<(number | boolean)[]>>(
-	pSeries<number | boolean>(new Set([() => Promise.resolve(1), () => true]))
+expectType<Promise<Array<number | boolean>>>(
+	pSeries<number | boolean>(new Set([async () => Promise.resolve(1), () => true])),
 );

package.json

@@ -10,8 +10,10 @@
 		"email": "sindresorhus@gmail.com",
 		"url": "https://sindresorhus.com"
 	},
+	"type": "module",
+	"exports": "./index.js",
 	"engines": {
-		"node": ">=8"
+		"node": "^12.20.0 || ^14.13.1 || >=16.0.0"
 	},
 	"scripts": {
 		"test": "xo && ava && tsd"
@@ -38,13 +40,9 @@
 		"promises",
 		"bluebird"
 	],
-	"dependencies": {
-		"@sindresorhus/is": "^0.15.0",
-		"p-reduce": "^2.1.0"
-	},
 	"devDependencies": {
-		"ava": "^1.4.1",
-		"tsd": "^0.7.2",
-		"xo": "^0.24.0"
+		"ava": "^3.15.0",
+		"tsd": "^0.17.0",
+		"xo": "^0.44.0"
 	}
 }

readme.md

@@ -2,6 +2,8 @@
 
 > Run promise-returning & async functions in series
 
+*Note:* You can just use `await` in a for-loop to get the same behavior. This package was useful before async/await existed.
+
 If you're doing the same work in each function, use [`p-each-series`](https://github.com/sindresorhus/p-each-series) instead.
 
 See [`p-all`](https://github.com/sindresorhus/p-all) for a concurrent counterpart.
@@ -15,18 +17,16 @@ $ npm install p-series
 ## Usage
 
 ```js
-const pSeries = require('p-series');
-const got = require('got');
-
-(async () => {
-	const tasks = [
-		() => got('https://sindresorhus.com'),
-		() => checkSomething(),
-		() => doSomethingElse()
-	];
-
-	console.log(await pSeries(tasks));
-})();
+import pSeries from 'p-series';
+import got from 'got';
+
+const tasks = [
+	() => got('https://sindresorhus.com'),
+	() => checkSomething(),
+	() => doSomethingElse()
+];
+
+console.log(await pSeries(tasks));
 ```
 
 ## API

test.js

@@ -1,20 +1,24 @@
 import test from 'ava';
-import pSeries from '.';
+import pSeries from './index.js';
 
 test('main', async t => {
 	const input = [
 		async () => 1 + 1,
 		() => 2 + 2,
-		async () => 3 + 3
+		async () => 3 + 3,
 	];
 
 	t.deepEqual(await pSeries(input), [2, 4, 6]);
 
 	const fixtureError = new Error('fixture');
-	await t.throwsAsync(pSeries([async () => Promise.reject(fixtureError)]), fixtureError.message);
+	await t.throwsAsync(pSeries([async () => Promise.reject(fixtureError)]), {
+		message: fixtureError.message,
+	});
 });
 
 test('throw if input is not a function', async t => {
 	const input = [Promise.resolve(1 + 1)];
-	await t.throwsAsync(pSeries(input), 'Expected task to be a `Function`, received `Promise`');
+	await t.throwsAsync(pSeries(input), {
+		message: 'Expected task to be a `Function`, received `object`',
+	});
 });