README.md 124 KB
Newer Older
2001
2002
2003
2004
2005
2006
2007
npm install -g serve
serve -s build
```

The last command shown above will serve your static site on the port **5000**. Like many of [serve](https://github.com/zeit/serve)’s internal settings, the port can be adjusted using the `-p` or `--port` flags.

Run this command to get a full list of the options available:
2008
2009

```sh
2010
serve -h
2011
2012
```

2013
2014
2015
2016
2017
### Other Solutions

You don’t necessarily need a static server in order to run a Create React App project in production. It works just as fine integrated into an existing dynamic one.

Here’s a programmatic example using [Node](https://nodejs.org/) and [Express](http://expressjs.com/):
2018
2019
2020
2021
2022
2023

```javascript
const express = require('express');
const path = require('path');
const app = express();

2024
app.use(express.static(path.join(__dirname, 'build')));
2025

Joe Haddad's avatar
Joe Haddad committed
2026
app.get('/', function(req, res) {
2027
  res.sendFile(path.join(__dirname, 'build', 'index.html'));
2028
2029
2030
2031
2032
});

app.listen(9000);
```

2033
2034
2035
The choice of your server software isn’t important either. Since Create React App is completely platform-agnostic, there’s no need to explicitly use Node.

The `build` folder with static assets is the only output produced by Create React App.
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045

However this is not quite enough if you use client-side routing. Read the next section if you want to support URLs like `/todos/42` in your single-page app.

### Serving Apps with Client-Side Routing

If you use routers that use the HTML5 [`pushState` history API](https://developer.mozilla.org/en-US/docs/Web/API/History_API#Adding_and_modifying_history_entries) under the hood (for example, [React Router](https://github.com/ReactTraining/react-router) with `browserHistory`), many static file servers will fail. For example, if you used React Router with a route for `/todos/42`, the development server will respond to `localhost:3000/todos/42` properly, but an Express serving a production build as above will not.

This is because when there is a fresh page load for a `/todos/42`, the server looks for the file `build/todos/42` and does not find it. The server needs to be configured to respond to a request to `/todos/42` by serving `index.html`. For example, we can amend our Express example above to serve `index.html` for any unknown paths:

```diff
2046
 app.use(express.static(path.join(__dirname, 'build')));
2047
2048
2049

-app.get('/', function (req, res) {
+app.get('/*', function (req, res) {
2050
   res.sendFile(path.join(__dirname, 'build', 'index.html'));
2051
2052
2053
 });
```

2054
If you’re using [Apache HTTP Server](https://httpd.apache.org/), you need to create a `.htaccess` file in the `public` folder that looks like this:
2055
2056
2057
2058
2059
2060
2061
2062

```
    Options -MultiViews
    RewriteEngine On
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteRule ^ index.html [QSA,L]
```

2063
It will get copied to the `build` folder when you run `npm run build`.
2064
2065

If you’re using [Apache Tomcat](http://tomcat.apache.org/), you need to follow [this Stack Overflow answer](https://stackoverflow.com/a/41249464/4878474).
2066

2067
2068
Now requests to `/todos/42` will be handled correctly both in development and in production.

2069
2070
2071
2072
2073
2074
On a production build, and when you've [opted-in](#why-opt-in),
a [service worker](https://developers.google.com/web/fundamentals/primers/service-workers/) will automatically handle all navigation requests, like for
`/todos/42`, by serving the cached copy of your `index.html`. This
service worker navigation routing can be configured or disabled by
[`eject`ing](#npm-run-eject) and then modifying the
[`navigateFallback`](https://github.com/GoogleChrome/sw-precache#navigatefallback-string)
2075
2076
2077
and [`navigateFallbackWhitelist`](https://github.com/GoogleChrome/sw-precache#navigatefallbackwhitelist-arrayregexp)
options of the `SWPreachePlugin` [configuration](../config/webpack.config.prod.js).

2078
2079
2080
2081
2082
When users install your app to the homescreen of their device the default configuration will make a shortcut to `/index.html`. This may not work for client-side routers which expect the app to be served from `/`. Edit the web app manifest at [`public/manifest.json`](public/manifest.json) and change `start_url` to match the required URL scheme, for example:

```js
  "start_url": ".",
```
2083

2084
### Building for Relative Paths
2085

Dan Abramov's avatar
Dan Abramov committed
2086
By default, Create React App produces a build assuming your app is hosted at the server root.<br>
Dan Abramov's avatar
Dan Abramov committed
2087
2088
2089
2090
2091
2092
2093
2094
To override this, specify the `homepage` in your `package.json`, for example:

```js
  "homepage": "http://mywebsite.com/relativepath",
```

This will let Create React App correctly infer the root path to use in the generated HTML file.

2095
2096
2097
2098
**Note**: If you are using `react-router@^4`, you can root `<Link>`s using the `basename` prop on any `<Router>`.<br>
More information [here](https://reacttraining.com/react-router/web/api/BrowserRouter/basename-string).<br>
<br>
For example:
Joe Haddad's avatar
Joe Haddad committed
2099

2100
2101
2102
2103
2104
```js
<BrowserRouter basename="/calendar"/>
<Link to="/today"/> // renders <a href="/calendar/today">
```

2105
2106
#### Serving the Same Build from Different Paths

Joe Haddad's avatar
Joe Haddad committed
2107
> Note: this feature is available with `react-scripts@0.9.0` and higher.
2108
2109
2110
2111
2112
2113
2114
2115

If you are not using the HTML5 `pushState` history API or not using client-side routing at all, it is unnecessary to specify the URL from which your app will be served. Instead, you can put this in your `package.json`:

```js
  "homepage": ".",
```

This will make sure that all the asset paths are relative to `index.html`. You will then be able to move your app from `http://mywebsite.com` to `http://mywebsite.com/relativepath` or even `http://mywebsite.com/relative/path` without having to rebuild it.
2116

2117
2118
2119
2120
2121
2122
2123
2124
2125
### Customizing Environment Variables for Arbitrary Build Environments

You can create an arbitrary build environment by creating a custom `.env` file and loading it using [env-cmd](https://www.npmjs.com/package/env-cmd).

For example, to create a build environment for a staging environment:

1. Create a file called `.env.staging`
1. Set environment variables as you would any other `.env` file (e.g. `REACT_APP_API_URL=http://api-staging.example.com`)
1. Install [env-cmd](https://www.npmjs.com/package/env-cmd)
Joe Haddad's avatar
Joe Haddad committed
2126
2127
2128
2129
2130
   ```sh
   $ npm install env-cmd --save
   $ # or
   $ yarn add env-cmd
   ```
2131
1. Add a new script to your `package.json`, building with your new environment:
Joe Haddad's avatar
Joe Haddad committed
2132
2133
2134
2135
2136
2137
2138
   ```json
   {
     "scripts": {
       "build:staging": "env-cmd .env.staging npm run build"
     }
   }
   ```
2139
2140
2141
2142
2143
2144

Now you can run `npm run build:staging` to build with the staging environment config.
You can specify other environments in the same way.

Variables in `.env.production` will be used as fallback because `NODE_ENV` will always be set to `production` for a build.

2145
### [Azure](https://azure.microsoft.com/)
2146

2147
See [this](https://medium.com/@to_pe/deploying-create-react-app-on-microsoft-azure-c0f6686a4321) blog post on how to deploy your React app to Microsoft Azure.
2148

2149
2150
See [this](https://medium.com/@strid/host-create-react-app-on-azure-986bc40d5bf2#.pycfnafbg) blog post or [this](https://github.com/ulrikaugustsson/azure-appservice-static) repo for a way to use automatic deployment to Azure App Service.

2151
### [Firebase](https://firebase.google.com/)
2152

2153
Install the Firebase CLI if you haven’t already by running `npm install -g firebase-tools`. Sign up for a [Firebase account](https://console.firebase.google.com/) and create a new project. Run `firebase login` and login with your previous created Firebase account.
2154

2155
Then run the `firebase init` command from your project’s root. You need to choose the **Hosting: Configure and deploy Firebase Hosting sites** and choose the Firebase project you created in the previous step. You will need to agree with `database.rules.json` being created, choose `build` as the public directory, and also agree to **Configure as a single-page app** by replying with `y`.
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191

```sh
    === Project Setup

    First, let's associate this project directory with a Firebase project.
    You can create multiple project aliases by running firebase use --add,
    but for now we'll just set up a default project.

    ? What Firebase project do you want to associate as default? Example app (example-app-fd690)

    === Database Setup

    Firebase Realtime Database Rules allow you to define how your data should be
    structured and when your data can be read from and written to.

    ? What file should be used for Database Rules? database.rules.json
    ✔  Database Rules for example-app-fd690 have been downloaded to database.rules.json.
    Future modifications to database.rules.json will update Database Rules when you run
    firebase deploy.

    === Hosting Setup

    Your public directory is the folder (relative to your project directory) that
    will contain Hosting assets to uploaded with firebase deploy. If you
    have a build process for your assets, use your build's output directory.

    ? What do you want to use as your public directory? build
    ? Configure as a single-page app (rewrite all urls to /index.html)? Yes
    ✔  Wrote build/index.html

    i  Writing configuration info to firebase.json...
    i  Writing project information to .firebaserc...

    ✔  Firebase initialization complete!
```

2192
IMPORTANT: you need to set proper HTTP caching headers for `service-worker.js` file in `firebase.json` file or you will not be able to see changes after first deployment ([issue #2440](https://github.com/facebook/create-react-app/issues/2440)). It should be added inside `"hosting"` key like next:
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203

```
{
  "hosting": {
    ...
    "headers": [
      {"source": "/service-worker.js", "headers": [{"key": "Cache-Control", "value": "no-cache"}]}
    ]
    ...
```

2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
Now, after you create a production build with `npm run build`, you can deploy it by running `firebase deploy`.

```sh
    === Deploying to 'example-app-fd690'...

    i  deploying database, hosting
    ✔  database: rules ready to deploy.
    i  hosting: preparing build directory for upload...
    Uploading: [==============================          ] 75%✔  hosting: build folder uploaded successfully
    ✔  hosting: 8 files uploaded successfully
    i  starting release process (may take several minutes)...

    ✔  Deploy complete!

    Project Console: https://console.firebase.google.com/project/example-app-fd690/overview
    Hosting URL: https://example-app-fd690.firebaseapp.com
```

For more information see [Add Firebase to your JavaScript Project](https://firebase.google.com/docs/web/setup).

2224
### [GitHub Pages](https://pages.github.com/)
2225

Joe Haddad's avatar
Joe Haddad committed
2226
> Note: this feature is available with `react-scripts@0.2.0` and higher.
2227

Dan Abramov's avatar
Dan Abramov committed
2228
2229
#### Step 1: Add `homepage` to `package.json`

Alex Wilmer's avatar
Alex Wilmer committed
2230
2231
**The step below is important!**<br>
**If you skip it, your app will not deploy correctly.**
Dan Abramov's avatar
Dan Abramov committed
2232

2233
Open your `package.json` and add a `homepage` field for your project:
2234

2235
```json
2236
  "homepage": "https://myusername.github.io/my-app",
2237
2238
```

2239
2240
2241
2242
2243
2244
or for a GitHub user page:

```json
  "homepage": "https://myusername.github.io",
```

2245
or for a custom domain page:
Joe Haddad's avatar
Joe Haddad committed
2246

2247
2248
2249
2250
```json
  "homepage": "https://mywebsite.com",
```

2251
2252
Create React App uses the `homepage` field to determine the root URL in the built HTML file.

Dan Abramov's avatar
Dan Abramov committed
2253
#### Step 2: Install `gh-pages` and add `deploy` to `scripts` in `package.json`
Dan Abramov's avatar
Dan Abramov committed
2254

2255
Now, whenever you run `npm run build`, you will see a cheat sheet with instructions on how to deploy to GitHub Pages.
2256

2257
To publish it at [https://myusername.github.io/my-app](https://myusername.github.io/my-app), run:
2258
2259

```sh
2260
2261
2262
2263
2264
2265
2266
npm install --save gh-pages
```

Alternatively you may use `yarn`:

```sh
yarn add gh-pages
2267
2268
```

2269
Add the following scripts in your `package.json`:
2270

2271
```diff
2272
  "scripts": {
2273
2274
2275
2276
+   "predeploy": "npm run build",
+   "deploy": "gh-pages -d build",
    "start": "react-scripts start",
    "build": "react-scripts build",
2277
2278
```

2279
The `predeploy` script will run automatically before `deploy` is run.
2280

2281
2282
2283
2284
2285
If you are deploying to a GitHub user page instead of a project page you'll need to make two
additional modifications:

1. First, change your repository's source branch to be any branch other than **master**.
1. Additionally, tweak your `package.json` scripts to push deployments to **master**:
Joe Haddad's avatar
Joe Haddad committed
2286

2287
2288
2289
2290
2291
2292
2293
```diff
  "scripts": {
    "predeploy": "npm run build",
-   "deploy": "gh-pages -d build",
+   "deploy": "gh-pages -b master -d build",
```

Dan Abramov's avatar
Dan Abramov committed
2294
2295
#### Step 3: Deploy the site by running `npm run deploy`

2296
2297
2298
2299
2300
Then run:

```sh
npm run deploy
```
2301

2302
#### Step 4: Ensure your project’s settings use `gh-pages`
Dan Abramov's avatar
Dan Abramov committed
2303
2304
2305
2306
2307
2308

Finally, make sure **GitHub Pages** option in your GitHub project settings is set to use the `gh-pages` branch:

<img src="http://i.imgur.com/HUjEr9l.png" width="500" alt="gh-pages branch setting">

#### Step 5: Optionally, configure the domain
Dan Abramov's avatar
Dan Abramov committed
2309

2310
2311
You can configure a custom domain with GitHub Pages by adding a `CNAME` file to the `public/` folder.

2312
2313
2314
2315
2316
2317
Your CNAME file should look like this:

```
mywebsite.com
```

Dan Abramov's avatar
Dan Abramov committed
2318
2319
#### Notes on client-side routing

2320
GitHub Pages doesn’t support routers that use the HTML5 `pushState` history API under the hood (for example, React Router using `browserHistory`). This is because when there is a fresh page load for a url like `http://user.github.io/todomvc/todos/42`, where `/todos/42` is a frontend route, the GitHub Pages server returns 404 because it knows nothing of `/todos/42`. If you want to add a router to a project hosted on GitHub Pages, here are a couple of solutions:
Dan Abramov's avatar
Dan Abramov committed
2321

Joe Haddad's avatar
Joe Haddad committed
2322
2323
- You could switch from using HTML5 history API to routing with hashes. If you use React Router, you can switch to `hashHistory` for this effect, but the URL will be longer and more verbose (for example, `http://user.github.io/todomvc/#/todos/42?_k=yknaj`). [Read more](https://reacttraining.com/react-router/web/api/Router) about different history implementations in React Router.
- Alternatively, you can use a trick to teach GitHub Pages to handle 404 by redirecting to your `index.html` page with a special redirect parameter. You would need to add a `404.html` file with the redirection code to the `build` folder before deploying your project, and you’ll need to add code handling the redirect parameter to `index.html`. You can find a detailed explanation of this technique [in this guide](https://github.com/rafrex/spa-github-pages).
2324

2325
2326
2327
2328
#### Troubleshooting

##### "/dev/tty: No such a device or address"

Nick Bartlett's avatar
Nick Bartlett committed
2329
If, when deploying, you get `/dev/tty: No such a device or address` or a similar error, try the following:
2330
2331
2332

1. Create a new [Personal Access Token](https://github.com/settings/tokens)
2. `git remote set-url origin https://<user>:<token>@github.com/<user>/<repo>` .
2333
3. Try `npm run deploy` again
2334

2335
2336
2337
2338
2339
2340
2341
2342
##### "Cannot read property 'email' of null"

If, when deploying, you get `Cannot read property 'email' of null`, try the following:

1. `git config --global user.name '<your_name>'`
2. `git config --global user.email '<your_email>'`
3. Try `npm run deploy` again

2343
### [Heroku](https://www.heroku.com/)
2344

Dan Abramov's avatar
Dan Abramov committed
2345
Use the [Heroku Buildpack for Create React App](https://github.com/mars/create-react-app-buildpack).<br>
2346
You can find instructions in [Deploying React with Zero Configuration](https://blog.heroku.com/deploying-react-with-zero-configuration).
2347

2348
#### Resolving Heroku Deployment Errors
2349

2350
2351
2352
2353
2354
Sometimes `npm run build` works locally but fails during deploy via Heroku. Following are the most common cases.

##### "Module not found: Error: Cannot resolve 'file' or 'directory'"

If you get something like this:
2355

2356
```
2357
remote: Failed to create a production build. Reason:
2358
remote: Module not found: Error: Cannot resolve 'file' or 'directory'
2359
MyDirectory in /tmp/build_1234/src
2360
2361
```

2362
It means you need to ensure that the lettercase of the file or directory you `import` matches the one you see on your filesystem or on GitHub.
2363
2364

This is important because Linux (the operating system used by Heroku) is case sensitive. So `MyDirectory` and `mydirectory` are two distinct directories and thus, even though the project builds locally, the difference in case breaks the `import` statements on Heroku remotes.
2365

2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
##### "Could not find a required file."

If you exclude or ignore necessary files from the package you will see a error similar this one:

```
remote: Could not find a required file.
remote:   Name: `index.html`
remote:   Searched in: /tmp/build_a2875fc163b209225122d68916f1d4df/public
remote:
remote: npm ERR! Linux 3.13.0-105-generic
remote: npm ERR! argv "/tmp/build_a2875fc163b209225122d68916f1d4df/.heroku/node/bin/node" "/tmp/build_a2875fc163b209225122d68916f1d4df/.heroku/node/bin/npm" "run" "build"
```

In this case, ensure that the file is there with the proper lettercase and that’s not ignored on your local `.gitignore` or `~/.gitignore_global`.

2381
### [Netlify](https://www.netlify.com/)
2382

2383
**To do a manual deploy to Netlify’s CDN:**
2384
2385

```sh
Elie's avatar
Elie committed
2386
npm install netlify-cli -g
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
netlify deploy
```

Choose `build` as the path to deploy.

**To setup continuous delivery:**

With this setup Netlify will build and deploy when you push to git or open a pull request:

1. [Start a new netlify project](https://app.netlify.com/signup)
2. Pick your Git hosting service and select your repository
3. Click `Build your site`

Ville Immonen's avatar
Ville Immonen committed
2400
**Support for client-side routing:**
2401
2402
2403
2404
2405
2406
2407
2408
2409

To support `pushState`, make sure to create a `public/_redirects` file with the following rewrite rules:

```
/*  /index.html  200
```

When you build the project, Create React App will place the `public` folder contents into the build output.

2410
### [Now](https://zeit.co/now)
2411

2412
Now offers a zero-configuration single-command deployment. You can use `now` to deploy your app for free.
2413
2414
2415

1. Install the `now` command-line tool either via the recommended [desktop tool](https://zeit.co/download) or via node with `npm install -g now`.

2416
2. Build your app by running `npm run build`.
2417

2418
3. Move into the build directory by running `cd build`.
2419

2420
4. Run `now --name your-project-name` from within the build directory. You will see a **now.sh** URL in your output like this:
2421

Joe Haddad's avatar
Joe Haddad committed
2422
2423
2424
   ```
   > Ready! https://your-project-name-tpspyhtdtk.now.sh (copied to clipboard)
   ```
2425

Joe Haddad's avatar
Joe Haddad committed
2426
   Paste that URL into your browser when the build is complete, and you will see your deployed app.
2427

2428
Details are available in [this article.](https://zeit.co/blog/unlimited-static)
2429

2430
### [S3](https://aws.amazon.com/s3) and [CloudFront](https://aws.amazon.com/cloudfront/)
2431

2432
See this [blog post](https://medium.com/@omgwtfmarc/deploying-create-react-app-to-s3-or-cloudfront-48dae4ce0af) on how to deploy your React app to Amazon Web Services S3 and CloudFront.
2433

2434
### [Surge](https://surge.sh/)
2435

Dan Abramov's avatar
Dan Abramov committed
2436
2437
2438
Install the Surge CLI if you haven’t already by running `npm install -g surge`. Run the `surge` command and log in you or create a new account.

When asked about the project path, make sure to specify the `build` folder, for example:
2439
2440
2441
2442
2443

```sh
       project path: /path/to/project/build
```

Brian Ng's avatar
Brian Ng committed
2444
Note that in order to support routers that use HTML5 `pushState` API, you may want to rename the `index.html` in your build folder to `200.html` before deploying to Surge. This [ensures that every URL falls back to that file](https://surge.sh/help/adding-a-200-page-for-client-side-routing).
2445

2446
2447
2448
2449
## Advanced Configuration

You can adjust various development and production settings by setting environment variables in your shell or with [.env](#adding-development-environment-variables-in-env).

Joe Haddad's avatar
Joe Haddad committed
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
| Variable            |      Development       |     Production     | Usage                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
| :------------------ | :--------------------: | :----------------: | :----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| BROWSER             |   :white_check_mark:   |        :x:         | By default, Create React App will open the default system browser, favoring Chrome on macOS. Specify a [browser](https://github.com/sindresorhus/opn#app) to override this behavior, or set it to `none` to disable it completely. If you need to customize the way the browser is launched, you can specify a node script instead. Any arguments passed to `npm start` will also be passed to this script, and the url where your app is served will be the last argument. Your script's file name must have the `.js` extension.                                                                                                                                       |
| HOST                |   :white_check_mark:   |        :x:         | By default, the development web server binds to `localhost`. You may use this variable to specify a different host.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| PORT                |   :white_check_mark:   |        :x:         | By default, the development web server will attempt to listen on port 3000 or prompt you to attempt the next available port. You may use this variable to specify a different port.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| HTTPS               |   :white_check_mark:   |        :x:         | When set to `true`, Create React App will run the development server in `https` mode.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
| PUBLIC_URL          |          :x:           | :white_check_mark: | Create React App assumes your application is hosted at the serving web server's root or a subpath as specified in [`package.json` (`homepage`)](#building-for-relative-paths). Normally, Create React App ignores the hostname. You may use this variable to force assets to be referenced verbatim to the url you provide (hostname included). This may be particularly useful when using a CDN to host your application.                                                                                                                                                                                                                                               |
| CI                  | :large_orange_diamond: | :white_check_mark: | When set to `true`, Create React App treats warnings as failures in the build. It also makes the test runner non-watching. Most CIs set this flag by default.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
| REACT_EDITOR        |   :white_check_mark:   |        :x:         | When an app crashes in development, you will see an error overlay with clickable stack trace. When you click on it, Create React App will try to determine the editor you are using based on currently running processes, and open the relevant source file. You can [send a pull request to detect your editor of choice](https://github.com/facebook/create-react-app/issues/2636). Setting this environment variable overrides the automatic detection. If you do it, make sure your systems [PATH](<https://en.wikipedia.org/wiki/PATH_(variable)>) environment variable points to your editor’s bin folder. You can also set it to `none` to disable it completely. |
| CHOKIDAR_USEPOLLING |   :white_check_mark:   |        :x:         | When set to `true`, the watcher runs in polling mode, as necessary inside a VM. Use this option if `npm start` isn't detecting changes.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
| GENERATE_SOURCEMAP  |          :x:           | :white_check_mark: | When set to `false`, source maps are not generated for a production build. This solves OOM issues on some smaller machines.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
| NODE_PATH           |   :white_check_mark:   | :white_check_mark: | Same as [`NODE_PATH` in Node.js](https://nodejs.org/api/modules.html#modules_loading_from_the_global_folders), but only relative folders are allowed. Can be handy for emulating a monorepo setup by setting `NODE_PATH=src`.                                                                                                                                                                                                                                                                                                                                                                                                                                            |
2462

2463
2464
## Troubleshooting

2465
2466
2467
2468
2469
### `npm start` doesn’t detect changes

When you save a file while `npm start` is running, the browser should refresh with the updated code.<br>
If this doesn’t happen, try one of the following workarounds:

Joe Haddad's avatar
Joe Haddad committed
2470
2471
2472
2473
2474
2475
- If your project is in a Dropbox folder, try moving it out.
- If the watcher doesn’t see a file called `index.js` and you’re referencing it by the folder name, you [need to restart the watcher](https://github.com/facebook/create-react-app/issues/1164) due to a Webpack bug.
- Some editors like Vim and IntelliJ have a “safe write” feature that currently breaks the watcher. You will need to disable it. Follow the instructions in [“Adjusting Your Text Editor”](https://webpack.js.org/guides/development/#adjusting-your-text-editor).
- If your project path contains parentheses, try moving the project to a path without them. This is caused by a [Webpack watcher bug](https://github.com/webpack/watchpack/issues/42).
- On Linux and macOS, you might need to [tweak system settings](https://github.com/webpack/docs/wiki/troubleshooting#not-enough-watchers) to allow more watchers.
- If the project runs inside a virtual machine such as (a Vagrant provisioned) VirtualBox, create an `.env` file in your project directory if it doesn’t exist, and add `CHOKIDAR_USEPOLLING=true` to it. This ensures that the next time you run `npm start`, the watcher uses the polling mode, as necessary inside a VM.
2476

2477
If none of these solutions help please leave a comment [in this thread](https://github.com/facebook/create-react-app/issues/659).
2478

2479
### `npm test` hangs or crashes on macOS Sierra
2480

2481
If you run `npm test` and the console gets stuck after printing `react-scripts test` to the console there might be a problem with your [Watchman](https://facebook.github.io/watchman/) installation as described in [facebook/create-react-app#713](https://github.com/facebook/create-react-app/issues/713).
2482
2483
2484

We recommend deleting `node_modules` in your project and running `npm install` (or `yarn` if you use it) first. If it doesn't help, you can try one of the numerous workarounds mentioned in these issues:

Joe Haddad's avatar
Joe Haddad committed
2485
2486
2487
- [facebook/jest#1767](https://github.com/facebook/jest/issues/1767)
- [facebook/watchman#358](https://github.com/facebook/watchman/issues/358)
- [ember-cli/ember-cli#6259](https://github.com/ember-cli/ember-cli/issues/6259)
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498

It is reported that installing Watchman 4.7.0 or newer fixes the issue. If you use [Homebrew](http://brew.sh/), you can run these commands to update it:

```
watchman shutdown-server
brew update
brew reinstall watchman
```

You can find [other installation methods](https://facebook.github.io/watchman/docs/install.html#build-install) on the Watchman documentation page.

2499
If this still doesn’t help, try running `launchctl unload -F ~/Library/LaunchAgents/com.github.facebook.watchman.plist`.
2500

Joe Haddad's avatar
Joe Haddad committed
2501
There are also reports that _uninstalling_ Watchman fixes the issue. So if nothing else helps, remove it from your system and try again.
2502

2503
### `npm run build` exits too early
2504

2505
It is reported that `npm run build` can fail on machines with limited memory and no swap space, which is common in cloud environments. Even with small projects this command can increase RAM usage in your system by hundreds of megabytes, so if you have less than 1 GB of available memory your build is likely to fail with the following message:
2506

Joe Haddad's avatar
Joe Haddad committed
2507
> The build failed because the process exited too early. This probably means the system ran out of memory or someone called `kill -9` on the process.
2508
2509

If you are completely sure that you didn't terminate the process, consider [adding some swap space](https://www.digitalocean.com/community/tutorials/how-to-add-swap-on-ubuntu-14-04) to the machine you’re building on, or build the project locally.
2510

2511
2512
2513
### `npm run build` fails on Heroku

This may be a problem with case sensitive filenames.
2514
Please refer to [this section](#resolving-heroku-deployment-errors).
2515

2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
### Moment.js locales are missing

If you use a [Moment.js](https://momentjs.com/), you might notice that only the English locale is available by default. This is because the locale files are large, and you probably only need a subset of [all the locales provided by Moment.js](https://momentjs.com/#multiple-locale-support).

To add a specific Moment.js locale to your bundle, you need to import it explicitly.<br>
For example:

```js
import moment from 'moment';
import 'moment/locale/fr';
```

Mike Wilcox's avatar
Mike Wilcox committed
2528
If you are importing multiple locales this way, you can later switch between them by calling `moment.locale()` with the locale name:
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541

```js
import moment from 'moment';
import 'moment/locale/fr';
import 'moment/locale/es';

// ...

moment.locale('fr');
```

This will only work for locales that have been explicitly imported before.

2542
2543
### `npm run build` fails to minify

Dan Abramov's avatar
Edits    
Dan Abramov committed
2544
Before `react-scripts@2.0.0`, this problem was caused by third party `node_modules` using modern JavaScript features because the minifier couldn't handle them during the build. This has been solved by compiling standard modern JavaScript features inside `node_modules` in `react-scripts@2.0.0` and higher.
2545

Dan Abramov's avatar
Edits    
Dan Abramov committed
2546
If you're seeing this error, you're likely using an old version of `react-scripts`. You can either fix it by avoiding a dependency that uses modern syntax, or by upgrading to `react-scripts@>=2.0.0` and following the migration instructions in the changelog.
2547

2548
2549
## Alternatives to Ejecting

Joe Haddad's avatar
Joe Haddad committed
2550
[Ejecting](#npm-run-eject) lets you customize anything, but from that point on you have to maintain the configuration and scripts yourself. This can be daunting if you have many similar projects. In such cases instead of ejecting we recommend to _fork_ `react-scripts` and any other packages you need. [This article](https://auth0.com/blog/how-to-configure-create-react-app/) dives into how to do it in depth. You can find more discussion in [this issue](https://github.com/facebook/create-react-app/issues/682).
2551

Dan Abramov's avatar
Dan Abramov committed
2552
## Something Missing?
Dan Abramov's avatar
Dan Abramov committed
2553

2554
If you have ideas for more “How To” recipes that should be on this page, [let us know](https://github.com/facebook/create-react-app/issues) or [contribute some!](https://github.com/facebook/create-react-app/edit/master/packages/react-scripts/template/README.md)
For faster browsing, not all history is shown. View entire blame