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Last active February 6, 2023 15:02
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Watching build mode on Create React App

Create React App does not provide watching build mode oficially (#1070).

This script provides watching build mode for an external tool such as Chrome Extensions or Firebase app.

How to Use

Create a React app.

Put the script into scripts/watch.js.

Add watch task into the scripts block in package.json as follows:

  "scripts": {
    "start": "react-scripts start",
    // Add next line
    "watch": "node scripts/watch.js",
    "build": "react-scripts build",
    "test": "react-scripts test --env=jsdom",
    "eject": "react-scripts eject"

Run the watch task.

npm run watch

Change source code and check build output.

Directory structure may be following:

  • app/
    • src/
    • public/
    • scripts/
      • watch.js (need to add)
    • package.json (need to modify)
    • build/ (output)
process.env.NODE_ENV = 'development';
const fs = require('fs-extra');
const paths = require('react-scripts/config/paths');
const webpack = require('webpack');
const config = require('react-scripts/config/');
// removes react-dev-utils/webpackHotDevClient.js at first in the array
webpack(config).watch({}, (err, stats) => {
if (err) {
} else {
chunks: false,
colors: true
function copyPublicFolder() {
fs.copySync(paths.appPublic, paths.appBuild, {
dereference: true,
filter: file => file !== paths.appHtml
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with "react-scripts": "^4.0.3",

> node scripts/watch.js

INF | Serving assets from frontend DevServer URL: http://localhost:3000
DEB | [DevWebServer] Waiting for frontend DevServer 'http://localhost:3000' to be ready
  throw err;

Error: Cannot find module 'react-scripts/config/'
Require stack:
- /Users/sgtpooki/code/work/
    at Function.Module._resolveFilename (node:internal/modules/cjs/loader:933:15)
    at Function.Module._load (node:internal/modules/cjs/loader:778:27)
    at Module.require (node:internal/modules/cjs/loader:1005:19)
    at require (node:internal/modules/cjs/helpers:102:18)
    at Object.<anonymous> (/Users/sgtpooki/code/work/
    at Module._compile (node:internal/modules/cjs/loader:1101:14)
    at Object.Module._extensions..js (node:internal/modules/cjs/loader:1153:10)
    at Module.load (node:internal/modules/cjs/loader:981:32)
    at Function.Module._load (node:internal/modules/cjs/loader:822:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12) {
  requireStack: [
Dev command exited!

Use 'react-scripts/config/webpackDevServer.config.js' instead

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