51 lines
2.7 KiB
Markdown
51 lines
2.7 KiB
Markdown
# With universal configuration
|
|
|
|
This example shows how to use environment variables and customize one based on NODE_ENV for your application using `dotenv`, a `.env`-file and `next.config.js`.
|
|
|
|
When you build your application the environment variable is transformed into a primitive (string or undefined) and can only be changed with a new build. This happens for both client-side and server-side. If the environment variable is used directly in your application it will only have an effect on the server side, not the client side.
|
|
|
|
## Deploy your own
|
|
|
|
Deploy the example using [ZEIT Now](https://zeit.co/now):
|
|
|
|
[](https://zeit.co/import/project?template=https://github.com/zeit/next.js/tree/canary/examples/with-universal-configuration-build-time)
|
|
|
|
## How to use
|
|
|
|
### Using `create-next-app`
|
|
|
|
Execute [`create-next-app`](https://github.com/zeit/next.js/tree/canary/packages/create-next-app) with [npm](https://docs.npmjs.com/cli/init) or [Yarn](https://yarnpkg.com/lang/en/docs/cli/create/) to bootstrap the example:
|
|
|
|
```bash
|
|
npm init next-app --example with-universal-configuration-build-time with-universal-configuration-build-time-app
|
|
# or
|
|
yarn create next-app --example with-universal-configuration-build-time with-universal-configuration-build-time-app
|
|
```
|
|
|
|
### Download manually
|
|
|
|
Download the example:
|
|
|
|
```bash
|
|
curl https://codeload.github.com/zeit/next.js/tar.gz/canary | tar -xz --strip=2 next.js-canary/examples/with-universal-configuration-build-time
|
|
cd with-universal-configuration-build-time
|
|
```
|
|
|
|
Install it and run:
|
|
|
|
```bash
|
|
npm install
|
|
VARIABLE_EXAMPLE=next.js npm run dev
|
|
# or
|
|
yarn
|
|
VARIABLE_EXAMPLE=next.js yarn dev
|
|
```
|
|
|
|
Deploy it to the cloud with [ZEIT Now](https://zeit.co/import?filter=next.js&utm_source=github&utm_medium=readme&utm_campaign=next-example) ([Documentation](https://nextjs.org/docs/deployment)).
|
|
|
|
## Please note
|
|
|
|
- It is a bad practice to commit env vars to a repository. Thats why you should normally [gitignore](https://git-scm.com/docs/gitignore) your `.env` file.
|
|
- Any env var you expose in `next.config.js` will be publicly available and exposed to the client.
|
|
- 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 the example [with-universal-configuration-runtime](../with-universal-configuration-runtime).
|
|
- If you have many variables in `.env` and want to expose them without listing them all in `next.config.js`, see the example [with-dotenv](../with-dotenv). That example automatically exposes any variable that has been referenced in code, but keeps all other variables secret.
|