Return a plugin which logs initial build progress in webpack with live updates.

progress-plugin.js

/**
 * getProgressPlugin
 * Return a progress plugin instance which outputs build progress percentages in realtime
 *
 * @return {Object} A ProgressPlugin instance
 */
function getProgressPlugin() {
	var chars = 0, lastState, lastStateTime;
	return new webpack.ProgressPlugin(function(percentage, msg) {
		var state = msg;
		if (percentage < 1) {
			percentage = Math.floor(percentage * 100);
			msg = percentage + '%  ' + msg;
			if(percentage < 100) {
				msg = '  ' + msg;
			}
			if(percentage < 10) {
				msg = '  ' + msg;
			}
		}
		state = state.replace(/^\d+\/\d+\s+/, '');
		if (percentage === 0) {
			lastState = null;
			lastStateTime = +new Date();
		} else if (state !== lastState || percentage === 1) {
			var now = +new Date();
			if (lastState) {
				var stateMsg = (now - lastStateTime) + 'ms  ' + lastState;
				goToLineStart(stateMsg);
				process.stderr.write(stateMsg + '\n');
				chars = 0;
			}
			lastState = state;
			lastStateTime = now;
		}
		goToLineStart(msg);
		process.stderr.write(msg);
	});
	function goToLineStart(nextMessage) {
		var str = '';
		for(; chars > nextMessage.length; chars--) {
			str += '\b \b';
		}
		chars = nextMessage.length;
		for(var i = 0; i < chars; i++) {
			str += '\b';
		}
		if (str) {
			process.stderr.write(str);
		}
	}
}