An extension to the Promise prototype to "spread" resolved data from Promise.all() to multiple function parameters

promise.spread.js

Promise.prototype.spread = function(fn) {
	return this.then(function() {
		if (!arguments || arguments.length === 0) {
			return Promise.resolve(fn.apply());
		}
		if(typeof arguments[0] === 'object' && arguments[0].length > 0){
			return Promise.all(arguments[0]);
		}else{
			return Promise.resolve(arguments[0]);
		}
	})
	.then(function(args){
		if(args && !args.length){
			args = [args];
		}
		return fn.apply(null, args);
	});
};