function extend (a, b) {
		for (let key in b) {
			if (b.hasOwnProperty(key)) {
				a[key] = b[key];
			}
		}
		return a;
	}
Extend one object with another one
@param {object} a The object to extend
@param {object} b The object which extends the other, overwrites existing keys
@returns {object} The merged object