@ngx-env/builder
Advanced tools
Easily inject environment variables into your Angular applications
process.env and import.meta.env usage in TypeScript
ng add @ngx-env/builder
.env (optional)NG_APP_VERSION=$npm_package_version
NG_APP_COMMIT=$GITHUB_SHA
NG_APP_ENABLE_SENTRY=false
@Component({
selector: "app-footer",
template: `{{ branch }} - {{ commit }}`,
})
export class MainComponent {
branch = import.meta.env.NG_APP_BRANCH_NAME; // Recommended
commit = process.env.NG_APP_COMMIT; // Deprecated
}
<!-- index.html -->
<head>
<title>NgApp on %NG_APP_BRANCH_NAME% - %NG_APP_COMMIT%</title>
</head>
npm start
# Command-line environment variables
NG_APP_BRANCH_NAME=$GITHUB_HEAD_REF ng test
NG_APP_ENABLE_SENTRY=true npm run build
Your project can consume variables declared in your environment as if they were declared locally in your JS files.
These environment variables can be useful for:
The environment variables will be defined for you on process.env (deprecated) and import.meta.env. For example, having an environment variable named NG_APP_NOT_SECRET_CODE will be exposed in your JS as process.env.NG_APP_NOT_SECRET_CODE and import.meta.env.NG_APP_NOT_SECRET_CODE.
The environment variables are embedded during the build time.
⚠ Important
Do not store any secrets (such as private API keys) in your Angular app!
Environment variables are embedded into the build, meaning anyone can view them by inspecting your app's files.
NG_APP_* or Custom PrefixYou must create custom environment variables beginning with NG_APP_ or using any custom prefix.
If you want to have a shorter prefix like NG_ or if you want to access some domain specific variables directly, you can set the prefix in the angular.json configuration. You can use any valid regular expression to filter the variables.
"architect": {
"build": {
"builder": "@ngx-env/builder:browser",
"options": {
...
"scripts": []
"ngxEnv": {
"prefix": "(ORG|GITHUB|)_"
}
}
}
}
or using ng config
ng config projects.YOUR_APP_NAME.architect.build.options.ngxEnv.prefix '(ORG|GITHUB|)_'
Any other variables not starting with NG_APP_ or your custom prefix will be ignored to avoid accidentally exposing a private key on the machine that could have the same name.
See how to use system environment variables.
Changing any environment variables will require you to restart the development server if it is running.
NG_APP_ENVThere is also a built-in environment variable called NG_APP_ENV. You can read it from import.meta.env.NG_APP_ENV.
By default NG_APP_ENV is set to NODE_ENV but you are free to override it.
Note that NG_APP_ENV remains available even if you define a custom prefix not matching NG_APP.
Having access to the NG_APP_ENV is also useful for performing actions conditionally:
if (import.meta.env.NG_APP_ENV !== "production") {
analytics.disable();
}
When you compile the app with npm run build, the minification step will strip out this condition, and the resulting bundle will be smaller.
You have two options to consume an environment variable in your component's template.
@Component({
selector: "app-footer",
})
export class FooterComponent {
version = import.meta.env.NG_APP_VERSION;
}
{{ version }}
env pipenpm install @ngx-env/core
import { NgxEnvModule } from "@ngx-env/core";
@NgModule({
declarations: [FoooterComponent],
imports: [CommonModule, NgxEnvModule],
})
export class FooterModule {}
{{ 'import.meta.env.NG_APP_ENV' | env }}
{{ 'NG_APP_ENV' | env }}
You can also access the environment variables starting with NG_APP_ in the index.html.
<!DOCTYPE html>
<html lang="en">
<head>
<title>NgApp on %NG_APP_BRANCH_NAME%</title>
</head>
<body>
<app-root></app-root>
</body>
</html>
Defining environment variables can vary between OSes. It’s also important to know that this manner is temporary for the life of the shell session.
set "NG_APP_NOT_SECRET_CODE=abcdef" && npm start
(Note: Quotes around the variable assignment are required to avoid a trailing whitespace.)
($env:NG_APP_NOT_SECRET_CODE = "abcdef") -and (npm start)
NG_APP_NOT_SECRET_CODE=abcdef npm start
.env with loading priorities@ngx-env/builder uses dotenv to support loading environment variables from .env files.
.env files are to be stored alongside the package.json.
@ngx-env/builder loads .env files with these specific names for the following NG_APP_ENV values, files on the top have less priority than files on the bottom.
An env file for a specific mode (e.g. .env.production) will take higher priority than a generic one (e.g. .env).
valid .env filenames | NG_APP_ENV=* | NG_APP_ENV=test |
|---|---|---|
.env | ✔️ | ✔️ |
.env.local | ✔️ | ✖️ |
.env.${NG_APP_ENV} | ✔️ | ✔️ |
.env.${NG_APP_ENV}.local | ✔️ | ✔️ |
In addition, environment variables that already exist when the CLI is executed have the highest priority and will not be overwritten by .env files. For example, when running NG_APP_SOME_KEY=123 ng serve.
Expanding .env
You can expand variables already available on your machine for use in your .env
For example:
NG_APP_VERSION=$npm_package_version
NG_APP_HOSTNAME=$HOSTNAME
Or expand variables local to the current .env file:
DOMAIN=www.example.com
NG_APP_FOO=$DOMAIN/foo
NG_APP_BAR=$DOMAIN/bar
@ngx-env/builder supports monorepo projects with multiple applications.
When you have multiple applications in your monorepo, you can define a common .env.* file in the root of your monorepo and override it in each application or any other subdirectory below the root.
This is useful when you have a common configuration for all applications and want to override it for a specific application.
In order to do that, you need to define the root property in the ngxEnv section of your angular.json file.
"ngxEnv": {
"prefix": "NGX_",
"root": "../../"
},
For example, you have the following directory structure:
/home/user/monorepo
apps
frontend1
.env
frontend2
.env.dev
.env
.env
.env.dev
and the configuration below in frontends' angular.json:
"ngxEnv": {
"prefix": "NGX_",
"root": "../../"
},
Consumed dot env files will be ordered by hierarchy as follows:
/home/user/monorepo/apps/frontend1/.env
/home/user/monorepo/.env.dev
/home/user/monorepo/.env
/home/user/monorepo/apps/frontend2/.env.dev
/home/user/monorepo/apps/frontend2/.env
/home/user/monorepo/.env.dev
/home/user/monorepo/.env
These root configurations are equivalent:
"root": "../../" "root": "../../.env" "root": "/home/user/monorepo" "root": "/home/user/monorepo/.env"@ngx-env/builder supports Nx projects with multiple applications.
Currently the schematics only supports Angular CLI projects, so you need to install the package and uppdate project.json manually.
npm add -D @ngx-env/builder
Replace every occurence of @angular-devkit/build-angular with @ngx-env/builder in project.json file.
declare var process: {
env: {
NG_APP_ENV: string;
[key: string]: any;
};
};
When you have multiple applications in your Nx workspace, you can define common .env.* files in the root of your workspace and override them in each application or any other subdirectory below the root. See Cascading Environment Variables for more details.
You can also checkout the sample Nx workspace here.
@ngx-env/builder can be used with Docker to provide environment-specific configuration during the build and deployment of an Angular application.
The Dockerfile below will build an Angular application with the NGX_API_URL environment variable set to the value of the NGX_API_URL build argument.
FROM node:18
# Get the arguments from the command line
ARG NGX_API_URL
# Set the environment variables
ENV NGX_API_URL=$NGX_API_URL
################### Build ans Serve the application ######################
# You can replace this part with your own build process
WORKDIR /app
RUN npx -y @angular/cli@15 new ng-app --defaults
WORKDIR /app/ng-app
# In your own project, you would rather have the dependencies in the package.json file
RUN npx ng add @ngx-env/builder --skip-confirmation
RUN npm add @ngx-env/core
# In your own project, you would rather have the configuration in the angular.json file
RUN npx ng config projects.ng-app.architect.build.options.ngxEnv.prefix 'NGX_'
# Some sample code to show that the environment variable is available
RUN echo 'console.log("NGX_API_URL", import.meta.env["NGX_API_URL"])' >>src/main.ts
RUN npm run build
EXPOSE 8080
CMD ["npx", "http-server", "dist/ng-app", "-p", "8080"]
################################################################
Build and run the Docker image:
docker build --build-arg NGX_API_URL=http://staging.api.com -t ngx-env-demo .
docker run -p 8080:8080 ngx-env-demo
If you are already using a custom builder like @angular-builders/custom-webpack or ngx-build-plus and you cannot replace them with @ngx-env/builder you can still use @dotenv-run/webpack.
npm add -D @dotenv-run/webpack
import { DotenvRunPlugin } from "@dotenv-run/webpack";
import type { Configuration } from "webpack";
export default (config: Configuration) => {
config.plugins?.push(
new DotenvRunPlugin({ prefix: "NGX", verbose: true, root: "../../" })
);
return config;
};
The webpack configuration might be different depending on your custom builder but the important part is to add the DotenvRunPlugin plugin.
@dotenv-run/webpack is created by the same author of @ngx-env/builder and is used by @ngx-env/builder under the hood.
You can find a sample project using @dotenv-run/webpack here.
Please give it a star if you find it useful. ❤️
import.meta.env notation@ngx-env/builder supports both widely used but deprecated process.env and the newly adopted import.meta.env notations.
The import.meta notation is a part of the ECMAScript standard, specifically the ECMAScript modules, which is widely adopted and supported by modern browsers and JavaScript environments. On the other hand, process.env is specific to Node.js and not available in the browser by default.
Usage process.env might introduce typing issues depending on whether your workspace references @types/node or not, process.env requires different TS configurations between the webapp and the server.
.env.d.ts fileinterface ImportMeta {
readonly env: ImportMetaEnv;
}
interface ImportMetaEnv {
/**
* Built-in environment variable.
* @see Docs https://github.com/chihab/dotenv-run/packages/angular#ng_app_env.
*/
readonly NG_APP_ENV: string;
// Add your environment variables below
// readonly NG_APP_API_URL: string;
[key: string]: any;
}
process.env or import.meta.env inside environment.ts filesWe recommend to consume environment variables in Angular environment files, for two reasons:
To avoid using process.env / import.meta.env in your business code.
If one day you decide that a variable is no longer linked to the environment but rather to an Angular configuration, you would only have to modify the environment files.
To be ready for the day when Angular would implement the consumption of environment variables directly in the CLI.
If the syntax proposed by Angular CLI to access the environment variables turns out to be different, you would only have to modify the environment files.
Note that @ngx-env/builder might eventually remove support of process.env in future releases.
Example:
environment.ts
export const environment = {
production: false,
baseUrl: import.meta.env.NG_APP.BASE_URL,
version: import.meta.env.NG_APP_VERSION,
};
footer.component.ts
import { environment } from "src/environments/environment";
@Injectable()
export class SomeService {
version = environment.version;
baseUrl = environment.baseUrl;
}
process variableIf you have issues with the process, you probably don't have the .env.d.ts file in your source folder.
This file is created by running ng add @ngx-env/builder.
Depending on your Angular version and your TS config, the file should either be defined this way:
declare var process: {
env: {
NG_APP_ENV: string;
[key: string]: any;
};
};
or this way (if your project references @types/node):
declare namespace NodeJS {
export interface ProcessEnv {
readonly NG_APP_ENV: string;
}
}
In general prefer using import.meta.env notation.
If you prefer using import.meta.env.NGX_SOME_VARIABLE instead of import.meta.env['NGX_SOME_VARIABLE'], you can update the following line in your tsconfig.json file:
-"noPropertyAccessFromIndexSignature": true,
+"noPropertyAccessFromIndexSignature": false,
I wrote an article on InDepth.dev explaining how it works.
MIT © Chihab Otmani
FAQs
Easily inject environment variables into your Angular applications
The npm package @ngx-env/builder receives a total of 10,048 weekly downloads. As such, @ngx-env/builder popularity was classified as popular.
We found that @ngx-env/builder demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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