Using environment variables in Angular applications

By default, Angular only provides the NODE_ENV variable when building the application. You may use process.env.NODE_ENV anywhere in your TS/JS source, and the build will inline this value in the output chunks.

Other variables, such as those prefixed by NX_ will not work in Angular. To add support for other environment variables, do the following.

First, install @types/node so we can use process.env in our code.

npm install --save-dev @types/node # Or with yarn yarn add --dev @types/node

Next, update the build and serve targets (in project.json or angular.json file), to the following.

{ "build": { // NOTE: change the executor to one that supports custom webpack config. "executor": "@nrwl/angular:webpack-browser", // snip "options": { // NOTE: This file needs to be created. "customWebpackConfig": { "path": "apps/myapp/webpack.config.js" } // snip } }, "serve": { // NOTE: use dev-server that supports custom webpack config. "executor": "@nrwl/angular:webpack-dev-server" // snip } }

Then, we can use DefinePlugin in our custom webpack.

const webpack = require('webpack'); function getClientEnvironment(configuration) { // Grab NODE_ENV and NX_* environment variables and prepare them to be // injected into the application via DefinePlugin in webpack configuration. const NX_APP = /^NX_/i; const raw = Object.keys(process.env) .filter((key) => NX_APP.test(key)) .reduce( (env, key) => { env[key] = process.env[key]; return env; }, { NODE_ENV: process.env.NODE_ENV || configuration, } ); // Stringify all values so we can feed into webpack DefinePlugin return { 'process.env': Object.keys(raw).reduce((env, key) => { env[key] = JSON.stringify(raw[key]); return env; }, {}), }; } module.exports = (config, options, context) => { config.plugins.push( new webpack.DefinePlugin(getClientEnvironment(context.configuration)) ); return config; };

Now, when we define variables in our .env file, such as...

# apps/myapp/.env NX_API_URL=http://localhost:3333

Finally, We can use environment variables in our code. For example,

import { enableProdMode } from '@angular/core'; import { platformBrowserDynamic } from '@angular/platform-browser-dynamic'; import { AppModule } from './app/app.module'; if (process.env['NODE_ENV'] === 'production') { enableProdMode(); } // This is defined in our .env file. console.log('>>> NX_API_URL', process.env['NX_API_URL']); platformBrowserDynamic() .bootstrapModule(AppModule) .catch((err) => console.error(err));

You should also update tsconfig.apps.json and tsconfig.spec.json files to include node types.

{ "extends": "./tsconfig.json", "compilerOptions": { // snip "types": ["node"] } // snip }

Using environment variables in index.html

While you cannot use variable in index.html, one workaround for this is to create different index.*.html files, such as, then swap it in different environments.

For example in project.json (or angular.json),

project.json or angular.json
{ "build": { "executor": "@angular-devkit/build-angular:browser", // snip "configurations": { "production": { // snip "fileReplacements": [ { "replace": "apps/myapp/src/environments/environment.ts", "with": "apps/myapp/src/environments/" }, { "replace": "apps/myapp/src/index.html", "with": "apps/myapp/src/" } ] } } } }

You can also customize your webpack configuration, similar to using DefinePlugin above. This approach will require post-processing the index.html file, and is out of scope for this guide.