imagemin-newer    

Minify images with imagemin only if they need to be updated

Install

npm install imagemin-newer

Use

To use as a plugin, just require it alongside imagemin, pass it the output folder for your images, and use it:

var newer = require('imagemin-newer')
var Imagemin = require('imagemin')
 
var imagemin = new Imagemin()
    .src('images/*.{gif,jpg,png,svg}')
    .use(newer('build/images'))
    .use(Imagemin.gifsicle())
    .use(Imagemin.jpegtran())
    .use(Imagemin.optipng())
    .use(Imagemin.svgo())
    .dest('build/images')
 
imagemin.run(function (err, files) {
  if (err) {
    throw err
  }
  console.log(files[0])
  // => {path: 'build/images/foo.jpg', contents: <Buffer 89 50 4e ...>}
  // the files array will now be only what actually needed updating
})

CLI

If you install globally (or run imagemin-newer via npm scripts) then you'll have access to a small command line tool as well. It doesn't have any of the options that imagemin has and it only accepts directories (no globs).

imagemin-newer <directory> <output>

Options:
  -d, --debug    turn on verbose logging                        [default: false]
  -h, --help     Show help
  -v, --version  Show version number

Examples:
  imagemin-newer source build    compress images in source and output to build

Why

If you automatically imagemin an entire folder when files change, you'll soon become tired of watching every image compress for no reason. Imagemin-newer checks to see if images have changed before optimizing them.

There are a lot of other ways to do this if you are using gulp, like gulp-changed or with gulp-watch (like this). So if you use gulp, just do that!

If you don't use gulp, this might be exactly what you're looking for.

Contribute

Contributions are welcome! This project uses the standard style, so you should use it too! npm test will automatically make sure the code is written to the standard and then run tests. If the tests pass, you are good to go!