Compares Underscore's extend method with React's merge helper.

merge_extend.js

var merge   = require('react/lib/merge');
var _   = require('underscore');

var a = {
	name: 'Tommy',
	specs: {
		height: {
			inches: 60,
			feet: 6.085
		},
		weight: 180
	}
};

var b = {
	name: 'Lawson',
	specs: {
		height: {
			inches: 62
		},
		weight: 190
	},
	actions: {
		play: function() {
			console.log('go play');
		}
	}
};

var c = function(){};
c.prototype.play = function() {
	console.log('c play');
};

var reactsMethod = merge(c.prototype,a);
var underscoresMethod = _.extend(c.prototype,a);

console.log(reactsMethod);
console.log(underscoresMethod);
console.log( JSON.stringify(reactsMethod) === JSON.stringify(underscoresMethod) );