Add a command for running all the packages devs in parallel (#283)

i still prefer the pnpm PR

Author: chee

README.md

@@ -19,6 +19,12 @@ You can then build all the packages:
 npm run build --workspaces=true
 ```
 
+When working on the packages, it can be helpful to have them rebuild on change:
+
+```sh
+npm run dev
+```
+
 ## Packages
 
 | Name                                                | Description                                                             | Version                                                                                                                         |

package-lock.json

@@ -21,6 +21,7 @@
   ],
   "version": "0.0.0",
   "scripts": {
+    "dev": "node scripts/parallel.js npm run dev",
     "prepare": "husky",
     "lint": "eslint --cache",
     "lint:fix": "npm run lint -- --fix",
@@ -37,6 +38,7 @@
     "eslint": "^9.0.0",
     "eslint-config-prettier": "^10.0.0",
     "eslint-plugin-n": "17.19.0",
+    "execa": "^8.0.1",
     "husky": "^9.0.0",
     "prettier": "^3.0.0",
     "typescript-eslint": "^8.33.0"

package.json

@@ -0,0 +1,36 @@
+import { execaCommand as run } from 'execa'
+import pkg from '../package.json' with { type: 'json' }
+import { createInterface } from 'node:readline'
+
+const args = process.argv.slice(2)
+if (!args.length) {
+  console.error('Usage: npm run parallel <command>')
+  throw new Error('No command provided')
+}
+const cmd = args.join(' ')
+const FORCE_COLOR = ['0', 'false', ''].includes(/** @type {string} */ (process.env.FORCE_COLOR)) ? undefined : '1'
+await Promise.all(
+  pkg.workspaces.map((cwd, index) => {
+    const name = cwd.split('/').pop()
+    const actor = run(cmd, {
+      cwd,
+      shell: true,
+      env: { ...process.env, FORCE_COLOR },
+    })
+    if (!actor.stdout || !actor.stderr) {
+      throw new Error(`No stdout or stderr for ${name} in ${cwd}`)
+    }
+    const color = `\x1b[${31 + (index % 6)}m`
+    const reset = '\x1b[0m'
+    const prefix = `${color}[${name}]${reset} `
+
+    createInterface({ input: actor.stdout }).on('line', (line) => {
+      process.stdout.write(`${prefix}${line}\n`)
+    })
+    createInterface({ input: actor.stderr }).on('line', (line) => {
+      process.stderr.write(`${prefix}${line}\n`)
+    })
+
+    return actor
+  }),
+)