explode-env

This is a simple utility to expand environment variables in a string, heavily inspired by Golang's os.Expand.

Regex free, and no dependencies. If you need to expand environment variables in a string, this is the tool for you.

Installation

npm install explode-env

Usage

explode

import { explode } from "explode-env";

// Works with ${USER} and $USER
const expanded = explode("Hello, $USER!", { USER: "world" });
console.log(expanded); // Hello, world!

explodeEnv

Alias for explode with process.env as the second argument.

import { explodeEnv } from "explode-env";

const expanded = explodeEnv("Hello, $USER!");
console.log(expanded); // Hello, <your username>!

Options

You can pass an options object as the third argument to explode and second argument to explodeEnv.

ignoreUnsetVars

If true, variables that are not set in the mapping will not be expanded.

import { explode } from "explode-env";

const expanded = explode(
  "Hello, $USER!, and $OTHERS!",
  { OTHERS: "User X, User Y" },
  {
    ignoreUnsetVars: true,
  }
);

console.log(expanded); // Hello, $USER!, and User X, User Y!

ignoreDefaultExpansion

If true, default expansion in the form of ${var:-default} or ${var:=default} will not be expanded.

Note: This will NOT work with $var:-default or $var:=default. For reference: https://pubs.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_06_02

import { explode } from "explode-env";

const expanded = explode(
  "Hello, ${WORLD:=World}! Welcome ${WORLD}!"
  {},
  {
    ignoreDefaultExpansion: false,
  }
);

console.log(expanded); // Hello, World! Welcome World!

import { explode } from "explode-env";

const expanded = explode(
  "Hello, ${WORLD:=World}! Welcome ${WORLD}!"
  {},
  {
    ignoreDefaultExpansion: true,
  }
);

console.log(expanded); // Hello, ! Welcome !

Running tests

npm test

Publishing a new version

npm version <major|minor|patch>
git push --tags

Then, GitHub Actions will take care of the rest.

License

MIT