refactor: use fs.promises

cli/run/getConfigPath.ts

@@ -1,13 +1,13 @@
-import { readdirSync } from 'fs';
+import { promises as fs } from 'fs';
 import { resolve } from 'path';
 import { cwd } from 'process';
 import { handleError } from '../logging';
 
 const DEFAULT_CONFIG_BASE = 'rollup.config';
 
-export function getConfigPath(commandConfig: string | true): string {
+export async function getConfigPath(commandConfig: string | true): Promise<string> {
 	if (commandConfig === true) {
-		return resolve(findConfigFileNameInCwd());
+		return resolve(await findConfigFileNameInCwd());
 	}
 	if (commandConfig.slice(0, 5) === 'node:') {
 		const pkgName = commandConfig.slice(5);
@@ -30,8 +30,8 @@ export function getConfigPath(commandConfig: string | true): string {
 	return resolve(commandConfig);
 }
 
-function findConfigFileNameInCwd(): string {
-	const filesInWorkingDir = new Set(readdirSync(cwd()));
+async function findConfigFileNameInCwd(): Promise<string> {
+	const filesInWorkingDir = new Set(await fs.readdir(cwd()));
 	for (const extension of ['mjs', 'cjs', 'ts']) {
 		const fileName = `${DEFAULT_CONFIG_BASE}.${extension}`;
 		if (filesInWorkingDir.has(fileName)) return fileName;

cli/run/index.ts

@@ -89,7 +89,7 @@ async function getConfigs(
 	command: any
 ): Promise<{ options: MergedRollupOptions[]; warnings: BatchWarnings }> {
 	if (command.config) {
-		const configFile = getConfigPath(command.config);
+		const configFile = await getConfigPath(command.config);
 		const { options, warnings } = await loadAndParseConfigFile(configFile, command);
 		return { options, warnings };
 	}

cli/run/loadConfigFile.ts

@@ -1,4 +1,4 @@
-import { realpathSync } from 'fs';
+import { promises as fs } from 'fs';
 import { extname, isAbsolute } from 'path';
 import { pathToFileURL } from 'url';
 import * as rollup from '../../src/node-entry';
@@ -57,7 +57,7 @@ async function loadConfigFile(
 	return getConfigList(configFileExport, commandOptions);
 }
 
-function getDefaultFromCjs(namespace: GenericConfigObject) {
+function getDefaultFromCjs(namespace: GenericConfigObject): unknown {
 	return namespace.__esModule ? namespace.default : namespace;
 }
 
@@ -103,7 +103,7 @@ async function getDefaultFromTranspiledConfigFile(
 }
 
 async function loadConfigFromBundledFile(fileName: string, bundledCode: string): Promise<unknown> {
-	const resolvedFileName = realpathSync(fileName);
+	const resolvedFileName = await fs.realpath(fileName);
 	const extension = extname(resolvedFileName);
 	const defaultLoader = require.extensions[extension];
 	require.extensions[extension] = (module: NodeModule, requiredFileName: string) => {

cli/run/watch-cli.ts

@@ -1,4 +1,4 @@
-import { type FSWatcher, readFileSync } from 'fs';
+import { type FSWatcher, promises } from 'fs';
 import chokidar from 'chokidar';
 import dateTime from 'date-time';
 import ms from 'pretty-ms';
@@ -22,7 +22,7 @@ export async function watch(command: Record<string, any>): Promise<void> {
 	let watcher: RollupWatcher;
 	let configWatcher: FSWatcher;
 	let resetScreen: (heading: string) => void;
-	const configFile = command.config ? getConfigPath(command.config) : null;
+	const configFile = command.config ? await getConfigPath(command.config) : null;
 
 	onExit(close);
 	process.on('uncaughtException', close);
@@ -40,7 +40,7 @@ export async function watch(command: Record<string, any>): Promise<void> {
 
 		async function reloadConfigFile() {
 			try {
-				const newConfigFileData = readFileSync(configFile, 'utf-8');
+				const newConfigFileData = await promises.readFile(configFile, 'utf8');
 				if (newConfigFileData === configFileData) {
 					return;
 				}

src/ModuleLoader.ts

@@ -253,7 +253,8 @@ export class ModuleLoader {
 		let source: LoadResult;
 		try {
 			source = await this.readQueue.run(
-				async () => (await this.pluginDriver.hookFirst('load', [id])) ?? (await readFile(id))
+				async () =>
+					(await this.pluginDriver.hookFirst('load', [id])) ?? (await readFile(id, 'utf8'))
 			);
 		} catch (err: any) {
 			timeEnd('load modules', 3);

src/utils/fs.ts

@@ -1,28 +1,10 @@
-import fs from 'fs';
+import { promises as fs } from 'fs';
 import { dirname } from './path';
 
-export * from 'fs';
+export const { lstat, readdir, readFile, realpath } = fs;
 
-export const readFile = (file: string): Promise<string> =>
-	new Promise<string>((fulfil, reject) =>
-		fs.readFile(file, 'utf-8', (err, contents) => (err ? reject(err) : fulfil(contents)))
-	);
-
-function mkdirpath(path: string) {
-	const dir = dirname(path);
-	fs.mkdirSync(dir, { recursive: true });
-}
-
-export function writeFile(dest: string, data: string | Uint8Array): Promise<void> {
-	return new Promise<void>((fulfil, reject) => {
-		mkdirpath(dest);
-
-		fs.writeFile(dest, data, err => {
-			if (err) {
-				reject(err);
-			} else {
-				fulfil();
-			}
-		});
-	});
+export async function writeFile(dest: string, data: string | Uint8Array): Promise<void> {
+	const dir = dirname(dest);
+	await fs.mkdir(dir, { recursive: true });
+	await fs.writeFile(dest, data);
 }

src/utils/resolveId.ts

@@ -1,6 +1,6 @@
 import { CustomPluginOptions, Plugin, ResolvedId, ResolveIdResult } from '../rollup/types';
 import { PluginDriver } from './PluginDriver';
-import { lstatSync, readdirSync, realpathSync } from './fs';
+import { lstat, readdir, realpath } from './fs';
 import { basename, dirname, isAbsolute, resolve } from './path';
 import { resolveIdViaPlugins } from './resolveIdViaPlugins';
 
@@ -45,26 +45,28 @@ export async function resolveId(
 	);
 }
 
-function addJsExtensionIfNecessary(file: string, preserveSymlinks: boolean) {
-	let found = findFile(file, preserveSymlinks);
-	if (found) return found;
-	found = findFile(file + '.mjs', preserveSymlinks);
-	if (found) return found;
-	found = findFile(file + '.js', preserveSymlinks);
-	return found;
+async function addJsExtensionIfNecessary(
+	file: string,
+	preserveSymlinks: boolean
+): Promise<string | undefined> {
+	return (
+		(await findFile(file, preserveSymlinks)) ??
+		(await findFile(file + '.mjs', preserveSymlinks)) ??
+		(await findFile(file + '.js', preserveSymlinks))
+	);
 }
 
-function findFile(file: string, preserveSymlinks: boolean): string | undefined {
+async function findFile(file: string, preserveSymlinks: boolean): Promise<string | undefined> {
 	try {
-		const stats = lstatSync(file);
+		const stats = await lstat(file);
 		if (!preserveSymlinks && stats.isSymbolicLink())
-			return findFile(realpathSync(file), preserveSymlinks);
+			return await findFile(await realpath(file), preserveSymlinks);
 		if ((preserveSymlinks && stats.isSymbolicLink()) || stats.isFile()) {
 			// check case
 			const name = basename(file);
-			const files = readdirSync(dirname(file));
+			const files = await readdir(dirname(file));
 
-			if (files.indexOf(name) !== -1) return file;
+			if (files.includes(name)) return file;
 		}
 	} catch {
 		// suppress

test/function/samples/max-parallel-file-reads-default/_config.js

@@ -1,24 +1,23 @@
 const assert = require('assert');
-const fs = require('fs');
+const { promises } = require('fs');
 
-const fsReadFile = fs.readFile;
+const fsReadFile = promises.readFile;
 let currentReads = 0;
 let maxReads = 0;
 
 module.exports = {
 	description: 'maxParallelFileReads not set',
 	before() {
-		fs.readFile = (path, options, callback) => {
+		promises.readFile = async (path, options) => {
 			currentReads++;
 			maxReads = Math.max(maxReads, currentReads);
-			fsReadFile(path, options, (err, data) => {
-				currentReads--;
-				callback(err, data);
-			});
+			const content = await fsReadFile(path, options);
+			currentReads--;
+			return content;
 		};
 	},
 	after() {
-		fs.readFile = fsReadFile;
+		promises.readFile = fsReadFile;
 		assert.strictEqual(maxReads, 5, 'Wrong number of parallel file reads: ' + maxReads);
 	}
 };

test/function/samples/max-parallel-file-reads-error/_config.js

@@ -1,8 +1,8 @@
-const fs = require('fs');
-const path = require('path');
+const { promises } = require('fs');
+const { join } = require('path');
 const { loader } = require('../../../utils.js');
 
-const fsReadFile = fs.readFile;
+const fsReadFile = promises.readFile;
 
 module.exports = {
 	description: 'maxParallelFileReads: fileRead error is forwarded',
@@ -13,19 +13,19 @@ module.exports = {
 		})
 	},
 	before() {
-		fs.readFile = (path, options, callback) => {
+		promises.readFile = (path, options) => {
 			if (path.endsWith('dep.js')) {
-				return callback(new Error('broken'));
+				throw new Error('broken');
 			}
 
-			fsReadFile(path, options, callback);
+			fsReadFile(path, options);
 		};
 	},
 	after() {
-		fs.readFile = fsReadFile;
+		promises.readFile = fsReadFile;
 	},
 	error: {
-		message: `Could not load ${path.join(__dirname, 'dep.js')} (imported by main): broken`,
-		watchFiles: ['main', path.join(__dirname, 'dep.js')]
+		message: `Could not load ${join(__dirname, 'dep.js')} (imported by main): broken`,
+		watchFiles: ['main', join(__dirname, 'dep.js')]
 	}
 };

test/function/samples/max-parallel-file-reads-infinity/_config.js

@@ -1,7 +1,7 @@
 const assert = require('assert');
-const fs = require('fs');
+const { promises } = require('fs');
 
-const fsReadFile = fs.readFile;
+const fsReadFile = promises.readFile;
 let currentReads = 0;
 let maxReads = 0;
 
@@ -11,17 +11,16 @@ module.exports = {
 		maxParallelFileReads: 0
 	},
 	before() {
-		fs.readFile = (path, options, callback) => {
+		promises.readFile = async (path, options) => {
 			currentReads++;
 			maxReads = Math.max(maxReads, currentReads);
-			fsReadFile(path, options, (err, data) => {
-				currentReads--;
-				callback(err, data);
-			});
+			const content = await fsReadFile(path, options);
+			currentReads--;
+			return content;
 		};
 	},
 	after() {
-		fs.readFile = fsReadFile;
+		promises.readFile = fsReadFile;
 		assert.strictEqual(maxReads, 5, 'Wrong number of parallel file reads: ' + maxReads);
 	}
 };

test/function/samples/max-parallel-file-reads-set/_config.js

@@ -1,7 +1,7 @@
 const assert = require('assert');
-const fs = require('fs');
+const { promises } = require('fs');
 
-const fsReadFile = fs.readFile;
+const fsReadFile = promises.readFile;
 let currentReads = 0;
 let maxReads = 0;
 
@@ -11,17 +11,16 @@ module.exports = {
 		maxParallelFileReads: 3
 	},
 	before() {
-		fs.readFile = (path, options, callback) => {
+		promises.readFile = async (path, options) => {
 			currentReads++;
 			maxReads = Math.max(maxReads, currentReads);
-			fsReadFile(path, options, (err, data) => {
-				currentReads--;
-				callback(err, data);
-			});
+			const content = await fsReadFile(path, options);
+			currentReads--;
+			return content;
 		};
 	},
 	after() {
-		fs.readFile = fsReadFile;
+		promises.readFile = fsReadFile;
 		assert.strictEqual(maxReads, 3, 'Wrong number of parallel file reads: ' + maxReads);
 	}
 };

test/function/samples/max-parallel-file-reads-with-plugin/_config.js

@@ -1,7 +1,7 @@
 const assert = require('assert');
-const fs = require('fs');
+const { promises } = require('fs');
 
-const fsReadFile = fs.readFile;
+const fsReadFile = promises.readFile;
 let currentReads = 0;
 let maxReads = 0;
 
@@ -11,26 +11,23 @@ module.exports = {
 		maxParallelFileReads: 3,
 		plugins: [
 			{
-				async load(id) {
-					return new Promise((fulfil, reject) =>
-						fs.readFile(id, 'utf-8', (err, contents) => (err ? reject(err) : fulfil(contents)))
-					);
+				load(id) {
+					return promises.readFile(id, 'utf-8');
 				}
 			}
 		]
 	},
 	before() {
-		fs.readFile = (path, options, callback) => {
+		promises.readFile = async (path, options) => {
 			currentReads++;
 			maxReads = Math.max(maxReads, currentReads);
-			fsReadFile(path, options, (err, data) => {
-				currentReads--;
-				callback(err, data);
-			});
+			const content = await fsReadFile(path, options);
+			currentReads--;
+			return content;
 		};
 	},
 	after() {
-		fs.readFile = fsReadFile;
+		promises.readFile = fsReadFile;
 		assert.strictEqual(maxReads, 3, 'Wrong number of parallel file reads: ' + maxReads);
 	}
 };