Example: Object.enableChaining(context2d) .setFillStyle('#333') .fillRect(0, 0, 30, 30) .rect(5, 5, 20, 20) .setFillStyle('#f90') .fill()

object-enable-chaining.js

Object.enableChaining = function (obj) {
	if (!obj || typeof obj !== 'object')
		throw new TypeError("Argument obj is not an Object");
	var names = {};
	var protos = [];
	var cur = obj;
	var descr;
	while (cur && protos.indexOf(cur) < 0) {
		descr = Object.getOwnPropertyDescriptors(cur);
		for (var k in descr) {
			if (!names[k] && descr[k].configurable && (descr[k].writeable || descr[k].set || typeof obj[k] === 'function'))
				names[k] = k;
		}
		protos.push(cur);
		cur = cur.constructor && cur.constructor.prototype || null;
	}
	function definePropertySetter(name) {
		var setterName = 'set' + name[0].toUpperCase() + name.slice(1);
		if (typeof obj[setterName] !== 'undefined')
			return;
		Object.defineProperty(obj, setterName, {
			configurable: true,
			value: function (value) {
				this[name] = value;
				return this;
			},
		});
	}
	function wrapProcedure(name) {
		if (typeof obj[name] !== 'function')
			return;
		var wrapperFunction = function () {
			wrapperFunction._originalFunction.apply(this, Array.prototype.slice.call(arguments, 0));
			return this;
		};
		wrapperFunction._originalFunction = obj[name];
		Object.defineProperty(obj, name, {
			configurable: true,
			value: wrapperFunction,
		});
	}
	for (var name in names) {
		if (typeof obj[name] === 'function')
			wrapProcedure(name);
		else
			definePropertySetter(name);
	}
	return obj;
};