如何在 Nuxt 2 或 3 中使用 .env 变量？

Question

I have.env file in the project root, and in my nuxt config I am using variables to configure ReCaptcha like this:

import dotenv from 'dotenv'
dotenv.config()

export default {
    modules: [
        ['@nuxtjs/recaptcha', {
          siteKey: process.env.RECAPTCHA_SITE_KEY,
          version: 3,
          size: 'compact'
        }],
    ]
}

and in.env like this:

RECAPTCHA_SITE_KEY=6L....

but the application always failed with console log error:

ReCaptcha error: No key provided

When I hard-code ReCaptcha key directly like that: siteKey: 6L.... app start working, so I guess the problem is with reading.env props in nuxt.config

do you have any idea how to fix it?

EDIT: I tried update my nuxt.config by @kissu recommendation and by example which I found here: https://www.npmjs.com/package/@nuxtjs/recaptcha

so there is new nuxt.config which also not working:

export default {
    modules: [
       '@nuxtjs/recaptcha',
    ],
    publicRuntimeConfig: {
       recaptcha: {
         siteKey: process.env.RECAPTCHA_SITE_KEY,
         version: 3,
         size: 'compact'
       }
  }
}

Answer 1

If your Nuxt version is 2.13 or above , you don't need to use @nuxtjs/dotenv or anything alike because it is already backed into the framework.

To use some variables, you need to have an .env file at the root of your project. This one should be ignored by git. You can then input some keys there like

PUBLIC_VARIABLE="https://my-cool-website.com"
PRIVATE_TOKEN="1234qwer"

In your nuxt.config.js , you have to input those into 2 objects, depending of your use case, either publicRuntimeConfig or privateRuntimeConfig :

export default {
  publicRuntimeConfig: {
    myPublicVariable: process.env.PUBLIC_VARIABLE,
  },
  privateRuntimeConfig: {
    myPrivateToken: process.env.PRIVATE_TOKEN
  }
}

Differences : publicRuntimeConfig can basically be used anywhere, while privateRuntimeConfig can only be used during SSR (a key can only stay private if not shipped to the browser).

A popular use case for the privateRuntimeConfig is to use it for nuxtServerInit or during the build process (either yarn build or yarn generate ) to populate the app with headless CMS' API calls.

More info can be found on this blog post: https://nuxtjs.org/blog/moving-from-nuxtjs-dotenv-to-runtime-config/

---

• Then, you will be able to access it into any .vue file directly with

this.$config.myPublicVariable

• You access it into Nuxt's /plugins too, with this syntax

export default ({ $axios, $config: { myPublicVariable } }) => {
  $axios.defaults.baseURL = myPublicVariable
}

• If you need this variable for a Nuxt module, write it directly with

process.env.PRIVATE_TOKEN

Sometimes, the syntax may differ a bit , in this case refer to your Nuxt module documentation.

// for @nuxtjs/gtm
publicRuntimeConfig: {
  gtm: {
    id: process.env.GOOGLE_TAG_MANAGER_ID
  }
},

---

PS: if you do use target: server (default value), you can yarn build and yarn start to deploy your app to production. Then, change any environment variables that you'd like and yarn start again. There will be no need for a rebuild. Hence the name RuntimeConfig !

Answer 2

It's very easy. Providing you an example with axios/nuxt

1. Define your variable in the .env file:

   baseUrl=http://localhost:1337

2. Add the variable in the nuxt.config.js in an env-object (and use it in the axios config):

   export default {env: {baseUrl: process.env.baseUrl},axios: {baseURL: process.env.baseUrl},}

3. Use the env variable in any file like so:

   console.log(process.env.baseUrl)

Note that console.log(process.env) will output {} but console.log(process.env.baseUrl) will still output your value!

Answer 3

You can also use the env property with Nuxt nuxt.config.js:

export default {
  // Environment variables
  env: {
    myVariable: process.env.NUXT_ENV_MY_VAR
  },
  ...
}

Then in your plugin:

const myVar = process.env.myVariable

Answer 4

For nuxt3 rc11, in nuxt.conf.ts file:

export default defineNuxtConfig({
  runtimeConfig: {
    public: {
      locale: {
        defaultLocale: process.env.NUXT_I18N_LOCALE,
        fallbackLocale: process.env.NUXT_I18N_FALLBACK_LOCALE,
      }
    }
  },
...

and in.env file:

NUXT_I18N_LOCALE=tr
NUXT_I18N_FALLBACK_LOCALE=en

public: is very important otherwise it cannot read it and gives undefined error.

Answer 5

For v3 there is a precise description in the official docs

You define a runtimeConfig entry in your nuxt.config.[ts,js] which works as initial / default value:

export default defineNuxtConfig({
  runtimeConfig: {
    recaptchaSiteKey: 'default value' // This key is "private" and will only be available within server-side
  }
}

You can also use env vars to init the runtimeConfig but its written static after build. But you can override the value at runtime by using the following env var:

NUXT_RECAPTCHA_SITE_KEY=SOMETHING DYNAMIC

If you need to use the config on client-side, you need to use the public property.

export default defineNuxtConfig({
  runtimeConfig: {
    public: {
      recaptchaSiteKey: 'default value' // will be also exposed to the client-side
    }
  }
}

Notice the PUBLIC part in the env var:

NUXT_PUBLIC_RECAPTCHA_SITE_KEY=SOMETHING DYNAMIC

Answer 6

This is very strange because we can't access process.env in Nuxt 3

In the Nuxt 3, we are invited to use the runtime config, but this is not always convenient, because the Nuxt application context is required.

But in a situation where we have some plain library, and we don't want to wrap it in plugins nor composables functions, declaring global variables through vite / webpack is best:

// nuxt.config.ts
export default defineNuxtConfig({
  vite: {
    define: {
      MY_API_URL: JSON.stringify(process.env.MY_API_URL)
    }
  }
})

And then you can use in any file without dancing with a tambourine:

// some-file.ts
console.log('global var:', MY_API_URL) // replaced by vite/webpack in real value