meta-next/src/Engine.js

const watchers = {}

const Engine = 
{
	app: null,
	container: null,
	canvas: null,
	gl: null,
	window: null,
	camera: null,

	defaultSettings: {
		width: 0,
		height: 0,
		antialias: true,
		upscale: true
	},

	on(event, func) 
	{
		const buffer = watchers[event]
		if(!buffer) {
			watchers[event] = [ func ]
		}
		else {
			buffer.push(func)
		}
	},

	off(event, func) 
	{
		const buffer = watchers[event]
		if(!buffer) { return }

		const index = buffer.indexOf(func)
		if(index === -1) { return }

		buffer[index] = buffer[buffer.length - 1]
		buffer.pop()
	},

	emit(event) 
	{
		const buffer = watchers[event]
		if(!buffer) { return }

		for(let n = 0; n < buffer.length; n++) {
			buffer[n]()
		}
	}
}

export default Engine