next.js/examples/with-universal-configuration/README.md

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# With universal configuration

## How to use

### Using `create-next-app`

Download [`create-next-app`](https://github.com/segmentio/create-next-app) to bootstrap the example:

```bash
npx create-next-app --example with-universal-configuration with-universal-configuration-app
# or
yarn create next-app --example with-universal-configuration with-universal-configuration-app
```

### Download manually

Download the example [or clone the repo](https://github.com/zeit/next.js):

```bash
curl https://codeload.github.com/zeit/next.js/tar.gz/canary | tar -xz --strip=2 next.js-canary/examples/with-universal-configuration
cd with-universal-configuration
```

Install it and run:

```bash
npm install
npm run dev
```

Deploy it to the cloud with [now](https://zeit.co/now) ([download](https://zeit.co/download))

```bash
now
```

## The idea behind the example

This example show how to set custom environment variables for your application based on NODE_ENV using [transform-define](https://github.com/FormidableLabs/babel-plugin-transform-define).

## Caveats

- Because a babel plugin is used the output is cached in `node_modules/.cache` by `babel-loader`. When modifying the configuration you will have to manually clear this cache to make changes visible. Alternately, you may skip caching for `babel-loader` as shown [here](https://github.com/zeit/next.js/issues/1103#issuecomment-279529809).
- This example sets the environment configuration at build time, meaning the same build might not be used in e.g. both staging and production. For a solution which sets the environment at runtime, see [here](https://github.com/zeit/next.js/issues/1488#issuecomment-289108931).