js: multimap and multireduce array methods

multimap_multireduce.js

Array.prototype.multimap = function(f) {
	return this.length == 0 ? [] : [(this[0] instanceof Array ? this[0].multimap(f) : f(this[0]))].concat(this.slice(1).multimap(f));
}

Array.prototype.multireduce = function(f, z) {
	return this.length == 0 ? z : f((this[0] instanceof Array ? this[0].multireduce(f, z) : this[0]), this.slice(1).multireduce(f, z));
}