@signalchain/rollup-plugin-env-gen

Config based generation of a .env and public variables file. Manage your environment secrets and public application variables from a single JavaScript file.

Works with Rollup and Vite.

Install

npm i -D @signalchain/rollup-plugin-env-gen

Sample Env

Optionally generate a modified version of the source file and produce a .sample file. (This is the default, but can be turned off by setting samplePath to false.) The sample file is identical to the input file with the exception that variables and secrets are converted to the zero value of their type.

For example:

• "Hello world!" ➡ ""
• 12345 ➡ 0
• true ➡ false

Public Vars

Public variables, such as those used in client side applications, will be generated only if the exported object has a publicVars field. There is a clear boundary at build time between publicVars and all other fields. That said, if you import secrets into client side code, they are visible to anyone who wants to poke at the source. So only include variables that are meant to be public in the publicVars object.

Runtime Template Variables

For runtime template strings in Public Env, wrap your template string like this ➡ "%YOUR_TEMPLATE_STRING%". Wrapping is required to keep the template string from being evaluated at build time. This feature only makes sense for public vars, so any template string outside of the publicVars object will be evaluated at build time.

Use

export type Options = {
	mode?: string // process.env.NODE_ENV
	inputPath?: string // [PROJECT_ROOT]/.env.js
	envPath?: string // [PROJECT_ROOT]/.env
	samplePath?: string | boolean // [PROJECT_ROOT]/.env.sample.js
	publicPath?: string // [PROJECT_ROOT]/src/publicVars.js
	watch?: boolean // true (WIP)
}

// rollup.config.js || vite.config.js
plugins: [envGen(Options)]

The inputPath defaults to [PROJECT_ROOT]/.env.js. That file exports a default object with a set of keys that will be used to match the mode option on build. If the publicVars key is in the exported object from the inputPath, it will generate a publicVars.js file at the publicPath. (Defaults to [PROJECT_ROOT]/src/publicVars.js.)

Example

// .env.js

const shared = {
	BOTH: true,
}

const development = {
	...shared,
	TEST: true,
}

const production = {
	...shared,
	TEST: false,
}

const sharedPublic = {
	PUBLIC: true,
}

const publicVars = {
	development: {
		...sharedPublic,
		TEMPLATED_TEMPLATE: "%`${window.location.host}`%",
	},
	production: {
		...sharedPublic,
	},
}

export default {
	development,
	production,
	publicVars,
}

.gitignore

If you don't want to commit your secrets to git, add the following to your .gitignore

# environment variables files
.env
.env*
!.env.sample.js

This says, "don't commit .env or .env<any other text>, but do commit .env.sample.js"