7d038dfef1
This updates old examples to the more universal `npx` command. Fixes https://github.com/vercel/next.js/discussions/12103 |
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.env | ||
next.config.js | ||
package.json | ||
README.md |
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 Vercel:
How to use
Using create-next-app
Execute create-next-app
with npm or Yarn to bootstrap the example:
npx create-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:
curl https://codeload.github.com/vercel/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:
npm install
VARIABLE_EXAMPLE=next.js npm run dev
# or
yarn
VARIABLE_EXAMPLE=next.js yarn dev
Deploy it to the cloud with Vercel (Documentation).
Please note
- It is a bad practice to commit env vars to a repository. Thats why you should normally 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.
- If you have many variables in
.env
and want to expose them without listing them all innext.config.js
, see the example with-dotenv. That example automatically exposes any variable that has been referenced in code, but keeps all other variables secret.