Javascript Binary heap data structure

Binary heap:- A binary heap is a complete binary tree which satisfies the heap ordering property. The ordering can be one of two types:

the min-heap property: the value of each node is greater than or equal to the value of its parent, with the minimum-value element at the root.
the max-heap property: the value of each node is less than or equal to the value of its parent, with the maximum-value element at the root.

let MinHeap = function() {
    let head = [null];
    this.insert = function(element) {
        head.push(element);
        if (head.length > 2) {
            let idx = head.length - 1;
            while (head[idx] < head[Math.floor(idx / 2)]) {
                if (idx >= 1) {
                    [head[Math.floor(idx / 2)], head[idx]] = [head[idx], head[Math.floor(idx / 2)]];
                    if (Math.floor(idx / 2) > 1) {
                        idx = Math.floor(idx / 2);
                    } else {
                        break;
                    }
                }
            }
        }
    }
}
let minHeap = new MinHeap();
minHeap.insert(2)
minHeap.insert(1)
minHeap.insert(3)
minHeap.insert(4)

let MaxHeap = function() {
    let head = [null];
    this.insert = function(element) {
        head.push(element);
        if (head.length > 2) {
            let idx = head.length - 1;
            while (head[idx] > head[Math.floor(idx / 2)]) {
                if (idx >= 1) {
                    [head[Math.floor(idx / 2)], head[idx]] = [head[idx], head[Math.floor(idx / 2)]];
                    if (Math.floor(idx / 2) > 1) {
                        idx = Math.floor(idx / 2);
                    } else {
                        break;
                    }
                }
            }
        }
    }
}
let maxHeap = new MaxHeap();
maxHeap.insert(2)
maxHeap.insert(1)
maxHeap.insert(3)
maxHeap.insert(4)

Any comments or suggestions are welcome.