Require Node.js 12.20 and move to ESM

.github/workflows/main.yml

@@ -10,11 +10,10 @@ jobs:
       fail-fast: false
       matrix:
         node-version:
-          - 14
-          - 12
+          - 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

@@ -1,7 +1,7 @@
 import {AsyncReturnType} from 'type-fest';
 
 // TODO: Move these to https://github.com/sindresorhus/type-fest
-type AsyncFunction = (...args: any[]) => Promise<unknown>;
+type AnyAsyncFunction = (...args: any[]) => Promise<unknown | void>;
 type ReplaceReturnType<T extends (...arguments_: any) => unknown, NewReturnType> = (...arguments_: Parameters<T>) => NewReturnType;
 
 /**
@@ -13,10 +13,10 @@ It uses the V8 serialization API to transfer arguments, return values, errors be
 
 @example
 ```
-import makeSynchronous = require('make-synchronous');
+import makeSynchronous from 'make-synchronous';
 
 const fn = makeSynchronous(async number => {
-	const delay = require('delay');
+	const {default: delay} = await import('delay');
 
 	await delay(100);
 
@@ -27,6 +27,4 @@ console.log(fn(2));
 //=> 4
 ```
 */
-declare function makeSynchronous<T extends AsyncFunction>(asyncFunction: T): ReplaceReturnType<T, AsyncReturnType<T>>;
-
-export = makeSynchronous;
+export default function makeSynchronous<T extends AnyAsyncFunction>(asyncFunction: T): ReplaceReturnType<T, AsyncReturnType<T>>;

index.js

@@ -1,18 +1,20 @@
-'use strict';
-const childProcess = require('child_process');
-const v8 = require('v8');
-const Subsume = require('subsume');
+import {Buffer} from 'node:buffer';
+import childProcess from 'node:child_process';
+import v8 from 'node:v8';
+import process from 'node:process';
+import Subsume from 'subsume';
 
 const HUNDRED_MEGABYTES = 1000 * 1000 * 100;
 
-module.exports = function_ => {
+export default function makeSynchronous(function_) {
 	return (...arguments_) => {
 		const serializedArguments = v8.serialize(arguments_).toString('hex');
 		const subsume = new Subsume();
 
+		// TODO: Use top-level await here when targeting Node.js 14.
 		const input = `
-			const v8 = require('v8');
-			const Subsume = require('subsume');
+			import v8 from 'node:v8';
+			import Subsume from 'subsume';
 
 			const subsume = new Subsume('${subsume.id}');
 
@@ -32,14 +34,14 @@ module.exports = function_ => {
 			})();
 		`;
 
-		const {error: subprocessError, stdout, stderr} = childProcess.spawnSync(process.execPath, ['-'], {
+		const {error: subprocessError, stdout, stderr} = childProcess.spawnSync(process.execPath, ['--input-type=module', '-'], {
 			input,
 			encoding: 'utf8',
 			maxBuffer: HUNDRED_MEGABYTES,
 			env: {
 				...process.env,
-				ELECTRON_RUN_AS_NODE: '1'
-			}
+				ELECTRON_RUN_AS_NODE: '1',
+			},
 		});
 
 		if (subprocessError) {
@@ -63,4 +65,4 @@ module.exports = function_ => {
 
 		return result;
 	};
-};
+}

index.test-d.ts

@@ -1,5 +1,5 @@
 import {expectType} from 'tsd';
-import makeSynchronous = require('.');
+import makeSynchronous from './index.js';
 
 const fn = makeSynchronous(async (number: number) => number * 2);
 

package.json

@@ -10,8 +10,10 @@
 		"email": "[email protected]",
 		"url": "https://sindresorhus.com"
 	},
+	"type": "module",
+	"exports": "./index.js",
 	"engines": {
-		"node": ">=12"
+		"node": "^12.20.0 || ^14.13.1 || >=16.0.0"
 	},
 	"scripts": {
 		"test": "xo && ava && tsd"
@@ -33,15 +35,15 @@
 		"async"
 	],
 	"dependencies": {
-		"subsume": "^3.0.0",
-		"type-fest": "^0.16.0"
+		"subsume": "^4.0.0",
+		"type-fest": "^2.3.3"
 	},
 	"devDependencies": {
-		"ava": "^2.4.0",
-		"delay": "^4.4.0",
-		"in-range": "^2.0.0",
-		"time-span": "^4.0.0",
-		"tsd": "^0.13.1",
-		"xo": "^0.33.0"
+		"ava": "^3.15.0",
+		"delay": "^5.0.0",
+		"in-range": "^3.0.0",
+		"time-span": "^5.0.0",
+		"tsd": "^0.17.0",
+		"xo": "^0.44.0"
 	}
 }

readme.md

@@ -10,17 +10,17 @@ This package works in Node.js only, not the browser.
 
 ## Install
 
-```
-$ npm install make-synchronous
+```sh
+npm install make-synchronous
 ```
 
 ## Usage
 
 ```js
-const makeSynchronous = require('make-synchronous');
+import makeSynchronous from 'make-synchronous';
 
 const fn = makeSynchronous(async number => {
-	const delay = require('delay');
+	const {default: delay} = await import('delay');
 
 	await delay(100);
 
@@ -37,7 +37,7 @@ console.log(fn(2));
 
 Returns a wrapped version of the given async function which executes synchronously. This means no other code will execute (not even async code) until the given async function is done.
 
-The given function is executed in a subprocess, so you cannot use any variables/imports from outside the scope of the function. You can pass in arguments to the function. To import dependencies, use either `require(…)` or `await import(…)` in the function body.
+The given function is executed in a subprocess, so you cannot use any variables/imports from outside the scope of the function. You can pass in arguments to the function. To import dependencies, use `await import(…)` in the function body.
 
 It uses the V8 serialization API to transfer arguments, return values, errors between the subprocess and the current process. It supports most values, but not functions and symbols.
 

test.js

@@ -1,14 +1,15 @@
-import {serial as test} from 'ava';
+import test from 'ava';
 import timeSpan from 'time-span';
 import inRange from 'in-range';
-import makeSynchronous from '.';
+import makeSynchronous from './index.js';
 
-test('main', t => {
+test.serial('main', t => {
 	const fixture = '🦄';
 	const end = timeSpan();
 
 	const result = makeSynchronous(async fixture => {
-		const delay = require('delay');
+		// eslint-disable-next-line node/no-unsupported-features/es-syntax
+		const {default: delay} = await import('delay');
 
 		await delay(200);
 
@@ -19,7 +20,7 @@ test('main', t => {
 	t.is(result, fixture);
 });
 
-test('error', t => {
+test.serial('error', t => {
 	t.throws(
 		() => {
 			makeSynchronous(async () => {
@@ -28,7 +29,7 @@ test('error', t => {
 		},
 		{
 			instanceOf: TypeError,
-			message: 'unicorn'
-		}
+			message: 'unicorn',
+		},
 	);
 });