Javascript Heap

heap.js

//takes an array, and a comparator for its elements
// e.g. function(a,b) {return a > b}
var heap = function(ary, comp) {
	this.array = [];
	this.comparator = comp;
	this._swap = function(a,b) {
		var tmp = this.array[a];
		this.array[a] = this.array[b];
		this.array[b] = tmp
	}

	this.extract_root = function() {
		var a    = this.array
		var cmp  = this.comparator
		this._swap( 0, a.length -1 )
		var root = a.pop()

		var current_index = 0
		var lchild_index = ( current_index * 2 ) + 1
		var rchild_index = lchild_index + 1

		while (!cmp( a[current_index], a[lchild_index] ) 
			|| !cmp( a[current_index], a[rchild_index] )) {

			if ( cmp ( a[rchild_index], a[lchild_index] ) 
				&& rchild_index <= a.length ) {
				this._swap( current_index, rchild_index )
				current_index = rchild_index
			} else if ( lchild_index < a.length ){
				this._swap( current_index, lchild_index )
				current_index = lchild_index
			} else {
				break;
			}
			lchild_index = ( current_index * 2 ) + 1
			rchild_index = lchild_index + 1
		}
		return root
	}

	this.insert = function(element) {
		this.array.push(element)
		var a   = this.array
		var cmp = this.comparator
		if (this.array.length == 1) return this
		var current_index = a.length - 1
		var parent_index  = Math.floor( ( current_index - 1 ) / 2 )
		while ( !cmp( a[ parent_index ],  a[ current_index ] ) ) {
			this._swap( current_index, parent_index )
			current_index = parent_index
			if (current_index == 0) return this
			parent_index = Math.floor( ( current_index - 1 ) / 2 )
		}
	}

	this.getShallowCopy = function(comp) {
		if (comp) return new heap(this.array, comp);
		return new heap(this.array, this.comparator);
	}

	this.getSortedArray = function() {
		var me = this.getShallowCopy();
		var array = [];
		while (me.count > 0) array.push(me.extract_root());
		return array;
	}
for (var i in ary) this.insert(ary[i])
return this;
}

var a = []
for (var i = 0; i < 1000; i++) a.push(Math.round(Math.random()*1000))
// a = [12,3,4]
var h = new heap(a,function(a,b){return a>b;})
var prev = h.extract_root()
for (var i = 0; i < a.length -1; i++) {
	var cur = h.extract_root()
	console.log(cur)
	if (cur > prev) return console.log('fail')
	prev = cur
}