refactor: use fs.promises in module loader

browser/fs.ts

@@ -1,4 +1,7 @@
 import { throwNoFileSystem } from './error';
 
-export const readFile = throwNoFileSystem('fs.readFile');
+export const promises = {
+	readFile: throwNoFileSystem('fs.readFile')
+};
+
 export const writeFile = throwNoFileSystem('fs.writeFile');

src/ModuleLoader.ts

@@ -29,7 +29,7 @@ import {
 	errUnresolvedImport,
 	errUnresolvedImportTreatedAsExternal
 } from './utils/error';
-import { readFile } from './utils/fs';
+import { promises as fs } from './utils/fs';
 import { isAbsolute, isRelative, resolve } from './utils/path';
 import { Queue } from './utils/queue';
 import relativeId from './utils/relativeId';
@@ -240,7 +240,8 @@ 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 fs.readFile(id, 'utf8'))
 			);
 		} catch (err: any) {
 			timeEnd('load modules', 3);

src/utils/fs.ts

@@ -1,28 +1,9 @@
-import fs from 'fs';
+import { promises as fs } from 'fs';
 import { dirname } from './path';
 
 export * from '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> {
+	await fs.mkdir(dirname(dest), { recursive: true });
+	await fs.writeFile(dest, data);
 }