README.md

rollup-plugin-imagemin

rollup-plugin-imagemin is a Rollup plugin that uses imagemin to optimize images in your Rollup build. If you've used imagemin on any other platform before, this will feel familiar to you.

Install

npm i rollup-plugin-imagemin --save-dev

Usage

// rollup.config.js
import { imagemin } from "rollup-plugin-imagemin";

export default {
  plugins: [
    imagemin()
  ],
  input: "src/index.js"
  output: {
    format: "esm",
    file: "./dist/index.js"
  }
};

// src/index.js
import someImage from "./some-image.png"; // <-- With the above config, this should output an optimized PNG to the dist folder.

Options

rollup-plugin-imagemin has number of useful options to help you tune your builds to your liking:

• disable (default: false): Disable all optimizations and output unoptimized images. Useful for speedier development builds.
• verbose (default: false): Enables verbose logging, such as optimization gains.
• emitFiles (default: true): Whether to emit files. Could be useful for server side builds. Be aware that unless disable is set to true, images will still be optimized in memory, but will not be written to disk.
• hashLength (default: 16): The length of hashes used in asset filenames.
• include (default: "**/*.{svg,png,jpg,jpeg,gif}"): File glob pattern of assets to be processed by rollup-plugin-imagemin.
• exclude (default: ""): File glob pattern of assets to not be processed by rollup-plugin-imagemin. The pattern defined by exclude is applied after the value of the include option pattern.
• fileName (default: "[name]-[hash][extname]"): The output filename pattern of images optimized by rollup-plugin-imagemin. The pattern includes the following tokens:
  • [name]: The basename of the input file.
  • [hash]: The has of the input file.
  • [extname]: The extension of the input file.
• publicPath (default: ""): A folder for where to put optimized assets. Use this to separate your images into a separate folder.
• preserveTree (default: false): If true, preserve directory structure relative to process.cwd(). Can also be a path specifying root from where directory structure should be preserved.
• gifsicle: (default: { optimizationLevel: 3 }): Settings to merge with default, to pass to imagemin-gifsicle.
• jpegtran (default: { progressive: true }): Settings to merge with default, to pass to imagemin-jpegtran.
• pngquant: (default: { speed: 1, strip: true }): Settings to merge with default, to pass to imagemin-pngquant.
• svgo: (default: { precision: 1, multipass: true }): Settings to merge with default, to pass to imagemin-svgo.
• plugins: object with plugin names as keys and plugins as value to pass to imagemin. By default, {gifsicle: 'imagemin-gifsicle', jpegtran: 'imagemin-jpegtran', pngquant: 'imagemin-pngquant', svgo: 'imagemin-svgo'} are used. Each plugin function must be a factory, taking the plugin's config (the object at options[pluginName], merged with defaults), and returning an imagemin buffer transformer.

Using custom plugins

You can use custom plugins the following way:

// rollup.config.js
import imagemin from "rollup-plugin-imagemin";
import myCustomPlugin from "imagemin-my-custom-plugin";

export default {
  plugins: [
    imagemin({
        myCustomPlugin: {
            // Config to pass to `myCustomPlugin`'s factory
        },
        plugins: {
            myCustomPlugin,
        }
    })
  ],
  input: "src/index.js"
  output: {
    format: "esm",
    file: "./dist/index.js"
  }
};

Contributing

Please read the contributing guidelines in CONTRIBUTING.md.

Special thanks

This is my first Rollup plugin. As such, I drew extensive help from the Rollup documentation, but also from the rollup-plugin-url and rollup-plugin-image source code. If anything in the plugin looks familiar to either of those two, it's no coincidence, and I owe a lot to the authors of those plugins for inspiration and guidance.