Replace run-parallel-limit with p-limit and use native promises

change/change-21b37dad-e52f-40ef-937e-eb775c98f1e9.json

@@ -0,0 +1,11 @@
+{
+  "changes": [
+    {
+      "packageName": "just-scripts",
+      "type": "minor",
+      "dependentChangeType": "patch",
+      "comment": "Replace `run-parallel-limit` with `p-limit`, and use native promises in `cleanTask`, `copyTask`, and `sassTask`",
+      "email": "198982749+Copilot@users.noreply.github.com"
+    }
+  ]
+}

packages/just-scripts/package.json

@@ -31,7 +31,7 @@
     "glob": "^13.0.6",
     "just-task": "workspace:^",
     "nano-spawn": "catalog:prod",
-    "run-parallel-limit": "^1.0.6",
+    "p-limit": "^7.3.1",
     "supports-color": "^8.1.0",
     "webpack-merge": "^6.0.1"
   },
@@ -181,7 +181,6 @@
   "devDependencies": {
     "@microsoft/api-extractor": "catalog:dev",
     "@microsoft/just-internal-scripts": "workspace:^",
-    "@types/run-parallel-limit": "^1.0.0",
     "@types/supports-color": "^8.1.1",
     "async-done": "^2.0.0",
     "autoprefixer": "catalog:dev",

packages/just-scripts/src/tasks/__tests__/cleanTask.spec.ts

@@ -7,10 +7,7 @@ jest.mock('just-task/lib/logger');
 
 // Mock fse.remove to track calls without actual filesystem operations
 jest.mock('fs-extra', () => ({
-  remove: jest.fn((_path, cb: (err: null) => void) => {
-    cb(null);
-    return Promise.resolve();
-  }),
+  remove: jest.fn(() => Promise.resolve()),
 }));
 const removeSpy = fse.remove as jest.MockedFunction<typeof fse.remove>;
 

packages/just-scripts/src/tasks/__tests__/copyTask.spec.ts

@@ -1,4 +1,4 @@
-import { describe, expect, it, jest, afterEach } from '@jest/globals';
+import { beforeAll, describe, expect, it, jest, afterEach } from '@jest/globals';
 import mockfs from 'mock-fs';
 import fse from 'fs-extra';
 import { Readable } from 'stream';
@@ -13,6 +13,12 @@ jest.mock('just-task/lib/logger');
 const itWindows = process.platform === 'win32' ? it : it.skip;
 
 describe('copyTask', () => {
+  beforeAll(async () => {
+    // Load the ESM-only `p-limit` used by copyTask up front, since it can't be loaded from disk
+    // while mock-fs is active.
+    await import('p-limit');
+  });
+
   afterEach(() => {
     mockfs.restore();
     // a couple tests mock additional functions

packages/just-scripts/src/tasks/cleanTask.ts

@@ -2,7 +2,6 @@ import fse from 'fs-extra';
 import path from 'path';
 import type { TaskFunction } from 'just-task';
 import { logger } from 'just-task';
-import parallelLimit from 'run-parallel-limit';
 
 export interface CleanTaskOptions {
   /**
@@ -24,16 +23,13 @@ export function defaultCleanPaths(): string[] {
 export function cleanTask(options?: CleanTaskOptions): TaskFunction {
   const { paths = defaultCleanPaths(), limit = 5 } = options || {};
 
-  return function clean(done: (err: Error | null) => void) {
+  return async function clean() {
     logger.info(`Removing [${paths.map(p => path.relative(process.cwd(), p)).join(', ')}]`);
 
-    const cleanTasks = paths.map(
-      cleanPath =>
-        function (cb: (error: Error | null) => void) {
-          fse.remove(cleanPath, cb);
-        },
-    );
+    // p-limit is ESM and must be async imported from CJS
+    const pLimit = (await import('p-limit')).default;
+    const limiter = pLimit(limit);
 
-    parallelLimit(cleanTasks, limit, done);
+    await Promise.all(paths.map(cleanPath => limiter(() => fse.remove(cleanPath))));
   };
 }

packages/just-scripts/src/tasks/copyTask.ts

@@ -1,10 +1,9 @@
 import { globSync, hasMagic } from 'glob';
 import fse from 'fs-extra';
 import path from 'path';
-import { pipeline } from 'stream';
+import { pipeline } from 'stream/promises';
 import type { TaskFunction } from 'just-task';
 import { logger } from 'just-task';
-import parallelLimit from 'run-parallel-limit';
 
 export interface CopyTaskOptions {
   /**
@@ -38,9 +37,8 @@ export interface CopyTaskOptions {
 export function copyTask(options: CopyTaskOptions): TaskFunction {
   const { paths, dest, limit = 15 } = options;
 
-  return function copy(done) {
+  return async function copy() {
     if (!paths?.length) {
-      done();
       return;
     }
 
@@ -54,13 +52,30 @@ export function copyTask(options: CopyTaskOptions): TaskFunction {
 
     fse.mkdirpSync(dest);
 
-    const copyTasks: parallelLimit.Task<void>[] = [];
+    // Source/destination pairs for all files to copy, collected before starting any copies
+    const filesToCopy: { src: string; dest: string }[] = [];
 
     for (const copyPath of normalizedPaths) {
       helper(copyPath, getBasePath(copyPath));
     }
 
-    parallelLimit(copyTasks, limit, done);
+    // p-limit is ESM and must be async imported from CJS
+    const pLimit = (await import('p-limit')).default;
+    const limiter = pLimit(limit);
+
+    await Promise.all(
+      filesToCopy.map(({ src, dest: destPath }) =>
+        limiter(async () => {
+          fse.mkdirpSync(path.dirname(destPath));
+
+          // Use `pipeline` rather than wiring up `pipe`/`end`/`error` manually: it resolves only
+          // after the destination has been fully flushed and closed (not merely when the source
+          // finishes reading), and destroys both streams on error so no file descriptors or
+          // partial destination files are leaked.
+          await pipeline(fse.createReadStream(src), fse.createWriteStream(destPath));
+        }),
+      ),
+    );
 
     function helper(srcGlob: string, basePath: string) {
       // Return absolute paths to ensure path.relative(basePath, matchedPath) works
@@ -86,17 +101,7 @@ export function copyTask(options: CopyTaskOptions): TaskFunction {
 
         const relativePath = path.relative(basePath, matchedPath);
 
-        copyTasks.push(cb => {
-          const destPath = path.join(dest, relativePath);
-
-          fse.mkdirpSync(path.dirname(destPath));
-
-          // Use `pipeline` rather than wiring up `pipe`/`end`/`error` manually: it invokes the
-          // callback exactly once, only after the destination has been fully flushed and closed
-          // (not merely when the source finishes reading), and destroys both streams on error so
-          // no file descriptors or partial destination files are leaked.
-          pipeline(fse.createReadStream(matchedPath), fse.createWriteStream(destPath), err => cb(err || null));
-        });
+        filesToCopy.push({ src: matchedPath, dest: path.join(dest, relativePath) });
       }
     }
   };

packages/just-scripts/src/tasks/sassTask.ts

@@ -3,7 +3,6 @@ import { globSync } from 'glob';
 import { logger, resolveCwd, type TaskFunction } from 'just-task';
 import path from 'path';
 import type { AcceptedPlugin } from 'postcss';
-import parallelLimit from 'run-parallel-limit';
 import { pathToFileURL } from 'url';
 import { tryRequire } from '../tryRequire';
 
@@ -25,7 +24,7 @@ export interface SassTaskOptions {
 export function sassTask(options: SassTaskOptions): TaskFunction {
   const { createSourceModule, postcssPlugins = [] } = options;
 
-  return function sass(done) {
+  return async function sass() {
     const sassModule = tryRequire<typeof import('sass')>('sass') || tryRequire<typeof import('sass')>('node-sass');
     const postcss = tryRequire<typeof import('postcss')>('postcss');
     const autoprefixer = tryRequire<typeof import('autoprefixer')>('autoprefixer');
@@ -42,64 +41,64 @@ export function sassTask(options: SassTaskOptions): TaskFunction {
         .filter(Boolean)
         .join(', ');
       logger.warn(`Required dependencies not found (${missing}), so this task has no effect.`);
-      done();
       return;
     }
 
     const autoprefixerFn = autoprefixer({ overrideBrowserslist: ['> 1%', 'last 2 versions', 'ie >= 11'] });
     const files = globSync('src/**/*.scss', { absolute: true, cwd: process.cwd() });
 
-    const tasks: parallelLimit.Task<void>[] = files.map(fileName => cb => {
-      fileName = path.resolve(fileName);
-
-      // The modern `compile()` API is available in `sass` but not in `node-sass`
-      if (typeof sassModule.compile === 'function') {
-        try {
-          const { css } = sassModule.compile(fileName, {
-            importers: [{ findFileUrl: patchSassFileUrl }],
-            loadPaths: [path.resolve(process.cwd(), 'node_modules')],
-          });
-          processCss(css);
-        } catch (err) {
-          const message = err instanceof Error ? err.message : String(err);
-          cb(new Error(`${path.relative(process.cwd(), fileName)}: ${message}`));
-        }
-      } else {
-        sassModule.render(
-          {
-            file: fileName,
-            importer: patchSassUrl,
-            includePaths: [path.resolve(process.cwd(), 'node_modules')],
-          },
-          (err, result) => {
-            if (err || !result) {
-              cb(new Error(`${path.relative(process.cwd(), fileName)}: ${err || 'no result returned'}`));
-              return;
+    // p-limit is ESM and must be async imported from CJS
+    const pLimit = (await import('p-limit')).default;
+    const limiter = pLimit(5);
+
+    await Promise.all(
+      files.map(file =>
+        limiter(async () => {
+          const fileName = path.resolve(file);
+
+          let css: string;
+          // The modern `compile()` API is available in `sass` but not in `node-sass`
+          if (typeof sassModule.compile === 'function') {
+            try {
+              css = sassModule.compile(fileName, {
+                importers: [{ findFileUrl: patchSassFileUrl }],
+                loadPaths: [path.resolve(process.cwd(), 'node_modules')],
+              }).css;
+            } catch (err) {
+              const message = err instanceof Error ? err.message : String(err);
+              throw new Error(`${path.relative(process.cwd(), fileName)}: ${message}`, { cause: err });
             }
-
-            processCss(result.css.toString());
-          },
-        );
-      }
-
-      function processCss(css: string) {
-        // eslint-disable-next-line @typescript-eslint/no-non-null-assertion -- always defined per above
-        postcss!([
-          autoprefixerFn,
-          ...(postcssRtl ? [postcssRtl({})] : []),
-          ...postcssPlugins,
-          ...(clean ? [clean()] : []),
-        ])
-          .process(css, { from: fileName })
-          .then(res => {
-            fs.writeFileSync(fileName + '.ts', createSourceModule(fileName, res.css));
-            cb(null);
-          })
-          .catch(e => cb(e instanceof Error ? e : new Error(String(e))));
-      }
-    });
-
-    parallelLimit(tasks, 5, done);
+          } else {
+            // The legacy `render()` API is callback-based, so it must be promisified
+            css = await new Promise<string>((resolve, reject) => {
+              sassModule.render(
+                {
+                  file: fileName,
+                  importer: patchSassUrl,
+                  includePaths: [path.resolve(process.cwd(), 'node_modules')],
+                },
+                (err, result) => {
+                  if (err || !result) {
+                    reject(new Error(`${path.relative(process.cwd(), fileName)}: ${err || 'no result returned'}`));
+                  } else {
+                    resolve(result.css.toString());
+                  }
+                },
+              );
+            });
+          }
+
+          const res = await postcss([
+            autoprefixerFn,
+            ...(postcssRtl ? [postcssRtl({})] : []),
+            ...postcssPlugins,
+            ...(clean ? [clean()] : []),
+          ]).process(css, { from: fileName });
+
+          fs.writeFileSync(fileName + '.ts', createSourceModule(fileName, res.css));
+        }),
+      ),
+    );
   };
 }
 

yarn.lock

@@ -2217,13 +2217,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@types/run-parallel-limit@npm:^1.0.0":
-  version: 1.0.3
-  resolution: "@types/run-parallel-limit@npm:1.0.3"
-  checksum: 10c0/499bf6640cf0c9ed6a20922117a247bcdaff8427ebde7f8237333f9966a82affe8504ae9c846193d4d19127be6aa291a10a8221b389a2bc47de6295c49146538
-  languageName: node
-  linkType: hard
-
 "@types/send@npm:*":
   version: 1.2.1
   resolution: "@types/send@npm:1.2.1"
@@ -6444,7 +6437,6 @@ __metadata:
   dependencies:
     "@microsoft/api-extractor": "catalog:dev"
     "@microsoft/just-internal-scripts": "workspace:^"
-    "@types/run-parallel-limit": "npm:^1.0.0"
     "@types/supports-color": "npm:^8.1.1"
     "@types/tar-fs": "npm:^2.0.4"
     async-done: "npm:^2.0.0"
@@ -6461,8 +6453,8 @@ __metadata:
     just-task: "workspace:^"
     mock-fs: "catalog:dev"
     nano-spawn: "catalog:prod"
+    p-limit: "npm:^7.3.1"
     postcss: "catalog:dev"
-    run-parallel-limit: "npm:^1.0.6"
     sass: "catalog:dev"
     supports-color: "npm:^8.1.0"
     tar-fs: "catalog:dev"
@@ -7367,6 +7359,15 @@ __metadata:
   languageName: node
   linkType: hard
 
+"p-limit@npm:^7.3.1":
+  version: 7.3.1
+  resolution: "p-limit@npm:7.3.1"
+  dependencies:
+    yocto-queue: "npm:^1.2.1"
+  checksum: 10c0/49b7d7fcc244d4659fa3b260c7b4e632bc72333c60e76e4cd24c7befdeb9b8e22da644e5064e83df9e2ded75245e3e3b9df0e9cf8500b08db8ebf58ac18c6764
+  languageName: node
+  linkType: hard
+
 "p-locate@npm:^4.1.0":
   version: 4.1.0
   resolution: "p-locate@npm:4.1.0"
@@ -8053,15 +8054,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"run-parallel-limit@npm:^1.0.6":
-  version: 1.1.0
-  resolution: "run-parallel-limit@npm:1.1.0"
-  dependencies:
-    queue-microtask: "npm:^1.2.2"
-  checksum: 10c0/9c78eb77e788d0ed803a7e80921412f6f6accfb2006de8c21699d9ebf7696df9cefaa313fe14d6169a3fc9f564b34fe91bfd9948cc3a58e2d24136a2390523ae
-  languageName: node
-  linkType: hard
-
 "run-parallel@npm:^1.1.9":
   version: 1.2.0
   resolution: "run-parallel@npm:1.2.0"
@@ -9753,3 +9745,10 @@ __metadata:
   checksum: 10c0/dceb44c28578b31641e13695d200d34ec4ab3966a5729814d5445b194933c096b7ced71494ce53a0e8820685d1d010df8b2422e5bf2cdea7e469d97ffbea306f
   languageName: node
   linkType: hard
+
+"yocto-queue@npm:^1.2.1":
+  version: 1.2.2
+  resolution: "yocto-queue@npm:1.2.2"
+  checksum: 10c0/36d4793e9cf7060f9da543baf67c55e354f4862c8d3d34de1a1b1d7c382d44171315cc54abf84d8900b8113d742b830108a1434f4898fb244f9b7e8426d4b8f5
+  languageName: node
+  linkType: hard