Change tags of all mp3s in directory from Title: Title (Artist) to Title: Title Artist: Artist

updateTags.js

//
// For all files in directory (mp3s), change Title and Artist tags
// From: Title: This is the name (this is the artist)
// To:  Title: This is the name Artist: this is the artist
// Must npm install node-id3 before running
const NodeID3 = require('node-id3');
var fs = require('fs');

const dir = process.argv[2];
if (!dir || dir.indexOf('-') === 0) {
	console.error("usage: node updateTags.js directory\nWill extract artist in parens from title tag and make artist tag\n");
	process.exit();
}

const updateTag = (file) => {
	console.log("processing:",file);
	const tags = NodeID3.read(file)
	let title = tags.title;
	console.log(tags.artist, tags.title);
	tags.title = tags.title.replace(/\(([^\)]+)\)/, function(repl,artist) {
		if (artist) {
			tags.artist = artist;
		}
			return '';
		});
	if (title !== tags.title) {
		console.log("updating");
		const success = NodeID3.write(tags, file) // Returns true/Error
	}
}

var files = fs.readdirSync(dir);
files.forEach(file => {
	updateTag(dir+'/'+file);
	console.log(dir+'/'+file);
});