README

@nickkaramoff/rollup-plugin-consts

Import build time constants with Rollup.

Heads up!

This package is a fork of rollup-plugin-consts. The difference is that this package uses a more powerful javascript-stringify instead of JSON.stringify() to support inserting richer objects and functions.

This fork can be used as a drop-in replacement.

Installation

npm install --save-dev @nickkaramoff/rollup-plugin-consts

yarn add --dev @nickkaramoff/rollup-plugin-consts

Usage

@nickkaramoff/rollup-plugin-consts let you use constants that are replaced at build time, such as inlining your NODE_ENV. Unlike similar plugins such as rollup-plugin-replace, @nickkaramoff/rollup-plugin-consts doesn't magically replace strings in your script. Instead, you import them like a module.

// script.js
import environment from 'consts:environment';

if (environment === 'production') {
    // Production only code ...
} else {
    // Development only code ...
}

All consts modules have the prefix consts: followed by the name of the constant, such as environment or testing. Rollup can reduce simple if statements like the one above.

// script.min.js

// environment == 'production'
{
    // Production only code ...
}

Generally, you need to ensure that @nickkaramoff/rollup-plugin-consts goes before other plugins (like rollup-plugin-commonjs), so that those can apply any optimisations such as dead code removal.

// rollup.config.js
import consts from '@nickkaramoff/rollup-plugin-consts';

export default {
    // ...
    plugins: [
        consts({
            environment: 'production',
        }),
    ],
};

Example

{
    // All options are treated as `string:*` replacers...

    testing: false, // 'string:testing' exports a boolean, and so on...
    version: '1.0.0',
    environment: 'development',
    config: { names: ['foo', 'bar'] }, // objects can be used as replacements too!
    sum: (a, b) => a + b, // ...and functions too!
}

TypeScript

The consts function is has a typings file. See Usage with TypeScript (in the original repo) to check how to create additional typings files for importing constants.

Credits

rollup-plugin-consts was originally created by Jake Archibald for PROXX. You can watch his presentation with Surma about Rollup plugins they wrote for PROXX.

The plugin was then worked on and published by Tiger Oakes.

License

Apache-2.0

Usage no npm install needed!