cli.js

#!/usr/bin/env node
'use strict';
const arrify = require('arrify');
const meow = require('meow');
const getStdin = require('get-stdin');
const imagemin = require('imagemin');
const ora = require('ora');
const plur = require('plur');
const stripIndent = require('strip-indent');
const pairs = require('lodash.pairs');

const cli = meow(`
	Usage
	  $ imagemin <path|glob> ... --out-dir=build [--plugin=<name> ...]
	  $ imagemin <file> > <output>
	  $ cat <file> | imagemin > <output>

	Options
	  --plugin, -p   Override the default plugins
	  --out-dir, -o  Output directory

	Examples
	  $ imagemin images/* --out-dir=build
	  $ imagemin foo.png > foo-optimized.png
	  $ cat foo.png | imagemin > foo-optimized.png
	  $ imagemin --plugin=pngquant foo.png > foo-optimized.png
	  $ imagemin --plugin.pngquant.quality={0.1,0.2} foo.png > foo-optimized.png
	  $ imagemin --plugin.webp.quality=95 --plugin.webp.preset=icon foo.png > foo-icon.webp
`, {
	flags: {
		plugin: {
			type: 'string',
			alias: 'p',
			default: [
				'gifsicle',
				'jpegtran',
				'optipng',
				'svgo'
			]
		},
		outDir: {
			type: 'string',
			alias: 'o'
		}
	}

});

const requirePlugins = plugins => plugins.map(([plugin, options]) => {
	try {
		return require(`imagemin-${plugin}`)(options);
	} catch (_) {
		console.error(stripIndent(`
			Unknown plugin: ${plugin}

			Did you forget to install the plugin?
			You can install it with:

			  $ npm install -g imagemin-${plugin}
		`).trim());

		process.exit(1);
	}
});

const normalizePluginOptions = plugin => {
	return pairs(arrify(plugin).reduce((m, v) => {
		return typeof v === 'object' ?
			{...m, ...v} :
			{[v]: {}, ...m};
	}, {}));
};

const run = async (input, {outDir, plugin} = {}) => {
	const pluginOpts = normalizePluginOptions(plugin);
	const plugins = requirePlugins(pluginOpts);
	const spinner = ora('Minifying images');

	if (Buffer.isBuffer(input)) {
		process.stdout.write(await imagemin.buffer(input, {plugins}));
		return;
	}

	if (outDir) {
		spinner.start();
	}

	let files;
	try {
		files = await imagemin(input, {destination: outDir, plugins});
	} catch (error) {
		spinner.stop();
		throw error;
	}

	if (!outDir && files.length === 0) {
		return;
	}

	if (!outDir && files.length > 1) {
		console.error('Cannot write multiple files to stdout, specify `--out-dir`');
		process.exit(1);
	}

	if (!outDir) {
		process.stdout.write(files[0].data);
		return;
	}

	spinner.stop();

	console.log(`${files.length} ${plur('image', files.length)} minified`);
};

if (cli.input.length === 0 && process.stdin.isTTY) {
	console.error('Specify at least one file path');
	process.exit(1);
}

(async () => {
	if (cli.input.length > 0) {
		await run(cli.input, cli.flags);
	} else {
		await run(await getStdin.buffer(), cli.flags);
	}
})();