MaxHeapWIthArray.js

//children are 2n + 1, 2
//parents are floor((n-1)/2)
class MaxHeap {

    constructor() {
        this.data = new Array(10);
        this.size = 0;
    }

    insert(value) {
        this.data[this.size] = value;
        var current = this.size;
        var parent;
        var temp;
        while (current > 0) {

            parent = Math.floor((current - 1) / 2);
            if (this.data[current] > this.data[parent]) {
                temp = this.data[current];
                this.data[current] = this.data[parent];
                this.data[parent] = temp;
            }

            current = parent;
        }

        this.size++;
    }

    remove() {

        if (this.size === 0)
            return;

        this.size--;
        var current = 0;
        var value = this.data[0];
        this.swap(0, this.size);


        while (current < this.size) {

            var left_pointer = 2 * current + 1;
            var right_pointer = 2 * current + 2;

            var has_right = (right_pointer < this.size) ? true : false;
            var has_left = (left_pointer < this.size) ? true : false;

            if (!has_left) {
                break;
            }

            //2 children
            if (has_left && has_right) {
                //check left vs right
                if (this.checkGreater(left_pointer, right_pointer)) {
                    if (this.data[left_pointer] > this.data[current]) {
                        this.swap(left_pointer, current);
                        current = left_pointer;
                    }else{
                        break;
                    }
                } else {
                    if (this.checkGreater(right_pointer, current)) {
                        this.swap(right_pointer, current);
                        current = right_pointer;
                    }else{
                        break;
                    }
                }
            } else {
                //only check left
                if (this.checkGreater(left_pointer, current)) {
                    this.swap(left_pointer, current);
                    current = left_pointer;
                }else{
                    break;
                }
            }           

        }
        return value;
    }

    swap(a, b) {
        var temp;
        temp = this.data[a];
        this.data[a] = this.data[b];
        this.data[b] = temp;
    }
    
    checkGreater(a, b){
        return (this.data[a] > this.data[b]);
    }
}

var maxHeap = new MaxHeap();
maxHeap.insert(10);
maxHeap.insert(0);
maxHeap.insert(3);
maxHeap.insert(4);
maxHeap.insert(20);
maxHeap.insert(-100);
maxHeap.insert(80);
console.log(maxHeap);
console.log(maxHeap.remove());
console.log(maxHeap.remove());
console.log(maxHeap.remove());
console.log(maxHeap.remove());
console.log(maxHeap.remove());
console.log(maxHeap.remove());
console.log(maxHeap.remove());