diff --git a/docs/guide/mode-and-env.md b/docs/guide/mode-and-env.md index 94fcbc940..f6cbf87f2 100644 --- a/docs/guide/mode-and-env.md +++ b/docs/guide/mode-and-env.md @@ -1,4 +1,34 @@ -# Environment Variables and Modes +# Modes and Environment Variables + +## Modes + +**Mode** is an important concept in Vue CLI projects. By default, there are three modes: + +- `development` is used by `vue-cli-service serve` +- `test` is used by `vue-cli-service test:unit` +- `production` is used by `vue-cli-service build` and `vue-cli-service test:e2e` + +You can overwrite the default mode used for a command by passing the `--mode` option flag. For example, if you want to use development variables in the build command: + +``` +vue-cli-service build --mode development +``` + +When running `vue-cli-service`, environment variables are loaded from all [corresponding files](#environment-variables). If they don't contain a `NODE_ENV` variable, it will be set accordingly. For example, `NODE_ENV` will be set to `"production"` in production mode, `"test"` in test mode, and defaults to `"development"` otherwise. + +Then `NODE_ENV` will determine the primary mode your app is runnning in - development, production or test - and consequently, what kind of webpack config will be created. + +With `NODE_ENV` set to "test" for example, Vue CLI creates a webpack config that is intended to be used and optimized for unit tests. It doesn't process images and other assets that are unnecessary for unit tests. + +Similarly, `NODE_ENV=development` creates a webpack configuration which enables HMR, doesn't hash assets or create vendor bundles in order to allow for fast re-builds when running a dev server. + +When you are running `vue-cli-service build`, your `NODE_ENV` should always be set to "production" to obtain an app ready for deployment, regardless of the environment you're deploying to. + +::: warning NODE_ENV +`NODE_ENV` and Vue CLI's mode are tightly linked. If you have set `NODE_ENV` in your environment outside of `.env` files, it will always determine the mode. You should either remove it or explicitly set `NODE_ENV` when running `vue-cli-service` commands, e.g. `NODE_ENV=production vue-cli-service build`. +::: + +## Environment Variables You can specify env variables by placing the following files in your project root: @@ -22,32 +52,10 @@ Loaded variables will become available to all `vue-cli-service` commands, plugin An env file for a specific mode (e.g. `.env.production`) will take higher priority than a generic one (e.g. `.env`). -In addition, environment variables that already exist when Vue CLI is bootstrapped have the highest priority and will not be overwritten by `.env` files. +In addition, environment variables that already exist when Vue CLI is executed have the highest priority and will not be overwritten by `.env` files. ::: -::: warning NODE_ENV -If you have a default `NODE_ENV` in your environment, you should either remove it or explicitly set `NODE_ENV` when running `vue-cli-service` commands. -::: - -## Modes - -**Mode** is an important concept in Vue CLI projects. By default, there are three modes in a Vue CLI project: - -- `development` is used by `vue-cli-service serve` -- `production` is used by `vue-cli-service build` and `vue-cli-service test:e2e` -- `test` is used by `vue-cli-service test:unit` - -Note that a mode is different from `NODE_ENV`, as a mode can contain multiple environment variables. That said, each mode does set `NODE_ENV` to the same value by default - for example, `NODE_ENV` will be set to `"development"` in development mode. - -You can set environment variables only available to a certain mode by postfixing the `.env` file. For example, if you create a file named `.env.development` in your project root, then the variables declared in that file will only be loaded in development mode. - -You can overwrite the default mode used for a command by passing the `--mode` option flag. For example, if you want to use development variables in the build command, add this to your `package.json` scripts: - -``` -"dev-build": "vue-cli-service build --mode development", -``` - -## Example: Staging Mode +### Example: Staging Mode Assuming we have an app with the following `.env` file: @@ -68,7 +76,7 @@ VUE_APP_TITLE=My App (staging) In both cases, the app is built as a production app because of the `NODE_ENV`, but in the staging version, `process.env.VUE_APP_TITLE` is overwritten with a different value. -## Using Env Variables in Client-side Code +### Using Env Variables in Client-side Code Only variables that start with `VUE_APP_` will be statically embedded into the client bundle with `webpack.DefinePlugin`. You can access them in your application code: @@ -97,7 +105,7 @@ module.exports = { ``` ::: -## Local Only Variables +### Local Only Variables Sometimes you might have env variables that should not be committed into the codebase, especially if your project is hosted in a public repository. In that case you should use an `.env.local` file instead. Local env files are ignored in `.gitignore` by default.