NOTE: This is a fork of the excellent @strattadb/environment, only created because issues/PRs don't seem to be being addressed in the original repo any more.
Environment variable configuration for Node.js made easy.
A lot of applications need to ensure that some environment variables are
set from the beginning, and checking if the value in process.env is undefined
every time is needed gets tedious very fast.
environment allows applications to ensure required env variables are set and are valid according
to your definition of valid. See how to use it.
- environment
- The problem
- Table of Contents
- Installation
- Usage
- Examples
- API
makeEnv(schema: Schema, processEnv?: { [key: string]: string | undefined }): Env- Parsers
parsers.string(value: string): stringparsers.boolean(value: string): booleanparsers.integer(value: string): numberparsers.float(value: string): numberparsers.email(value: string): stringparsers.url(value: string, opts?: any): stringparsers.ipAddress(value: string): stringparsers.port(value: string): numberparsers.whitelist(whitelistedValues: string[]): Parser<string>parsers.regex(pattern: Regex): Parser<string>parsers.array<T>({ parser: Parser<T>, separator?: string }): Parser<T>parsers.positiveInteger(value: string): numberparsers.nonPositiveInteger(value: string): numberparsers.negativeInteger(value: string): numberparsers.nonNegativeInteger(value: string): number
- Recipes
- FAQ
- Node.js support
- Contributing
- Maintainers
- Who's using environment
- Related libraries
- License
With Yarn:
yarn add @sadams/environmentor with npm:
npm install @sadams/environmentAn example env.js file:
// env.js
import { makeEnv, parsers } from '@sadams/environment';
const env = makeEnv({
nodeEnv: {
parser: parsers.whitelist(['production', 'development', 'test']),
required: true,
envVarName: 'NODE_ENV',
},
port: {
parser: parsers.port,
required: false,
defaultValue: 4000,
envVarName: 'PORT',
},
});
export default env;Now in a file:
// otherFile.js
import env from './env';
console.log(env.nodeEnv); // development
console.log(typeof env.nodeEnv); // string
console.log(env.port); // 4000
console.log(typeof env.port); // numberEnsures required env variables are present and returns an env object.
Supports passing a processEnv object as the second argument.
If it's not passed, it uses process.env.
This object will be used to look up the environment variables.
-
Schema:
- [key: string]:
object- Thekeywill be accessible in the returning env object.- parser:
function- A function that takes a string and can return anything. The return value will be accesible inenv[key]. If the argument is not valid, it should throw. - required:
boolean- Whether or not the env variable is required. If the valuetrueand the env variable is not set, it'll throw. If the value isfalseit'll look for the env variable inprocess.env, if isn't set, it'll usedefaultValue. - defaultValue:
any?- Only valid ifrequired: false. This is the default value of the env variable if it's not set. It won't be parsed or validated. - envVarName:
string- The name of the env variable to look up (process.env[envVarName]). - description:
string?- Helper text describing the variable.
- parser:
- [key: string]:
-
Env:
- [key: string]:
any- The keys are the same as the ones in the schema.
- [key: string]:
Trivial parser. It doesn't do any validation.
Ensures the value is a truthy or falsy value.
Truthy values: 'true', '1', 'yes', 'on'.
Falsy values: 'false', '0', 'no', 'off'.
Ensures the value is an integer.
Ensures the value is a float.
Ensures the value is an email.
Ensures the value is a url.
You can also pass the optional second argument opts which allows you to customise the validation rules.
See the isURL method of validator.js for a list of the options: https://github.com/validatorjs/validator.js
Ensures the value is an IP address.
Ensures the value is a port.
Takes a list of valid values and returns a parser that ensures the value is in the whitelist.
Example:
import { makeEnv, parsers } from '@sadams/environment';
const env = makeEnv({
color: {
parser: parsers.whitelilst(['red', 'blue', 'green']),
required: true,
envVarName: 'COLOR',
},
});Takes a regex and returns a parser that ensures the value matches the pattern.
Example:
import { makeEnv, parsers } from '@sadams/environment';
const env = makeEnv({
color: {
parser: parsers.regex(/^green$/),
required: true,
envVarName: 'COLOR',
},
});Takes a parser and returns a parser that parses a list of values.
The default value separator is ,.
Example:
import { makeEnv, parsers } from '@sadams/environment';
const env = makeEnv({
color: {
parser: parsers.array({ parser: parsers.integer }),
required: true,
envVarName: 'FAVORITE_NUMBERS',
},
});Ensures the value is a positive integer.
Ensures the value is a non-positive integer.
Ensures the value is a negative integer.
Ensures the value is a non-negative integer.
If required is true and the environment variable isn't set,
it'll throw:
// env.js
import { makeEnv, parsers } from '@sadams/environment';
const env = makeEnv({
notSet: {
parser: parsers.string,
required: true,
envVarName: 'NOT_SET',
},
});node env.js
EnvironmentVariableError: NOT_SET is required but is not set
at ...
...If the env variable is not required you must specify a default value:
import { makeEnv, parsers } from '@sadams/environment';
const env = makeEnv({
port: {
parser: parsers.port,
required: false,
defaultValue: 4000,
envVarName: 'PORT',
},
});
console.log(env.port); // 4000A parser function must take a string value and can return anything. The value you return is what you'll get in the env object. If the value is not valid you should throw an error:
import { makeEnv, parsers } from '@sadams/environment';
const env = makeEnv({
someValue: {
parser: (value) => {
if (value === 'forbiddenValue') {
throw new Error('value is forbidden');
}
return value;
},
required: true,
envVarName: 'SOME_VALUE',
},
});Usage with Dotenv
A common pattern is to load the env variables from a file using dotenv and then ensuring that the required variables are actually present:
const dotenv = require('dotenv');
dotenv.config(); // Loads env variables from `.env` file to `process.env`.
const { makeEnv, parsers } = require('@sadams/environment');
const env = makeEnv({
secretToken: {
parser: parsers.string,
required: true,
envVarName: 'SECRET_TOKEN',
},
});By default, makeEnv uses process.env to look up and get environment variables,
but you can pass you own processEnv object as the second argument that will
be used instead of process.env:
import { makeEnv, parsers } from '@sadams/environment';
const env = makeEnv(
{
hello: {
parser: parsers.string,
required: true,
envVarName: 'HELLO',
},
},
{
HELLO: 'WORLD',
},
);The best place to create the env object is very early
in your application startup.
Everything before you call makeEnv with your schema will
not be guaranteed to have your required env variables.
No, when you create an env object it will read the value of
process.env at that time. After that, if anything makes
changes to process.env, it will not be reflected in the
env object.
Can I use the debug module with environment?
Yes! Set DEBUG=environment.
Yes! You can have as many env objects as you want!
Node.js version 12 or higher. Every version of this library is tested in Node.js 12, 14 and 16.
PRs, feature requests, bug reports, and any kind of contributions are welcome! See CONTRIBUTING.md.
MIT test