03-Min-Heap.js

/* Heaps */

// left child: i * 2
// right child: i * 2 + 1
// parent: i / 2
const MinHeap = function () {
    const heap = [];

    this.print = () => heap;

    this.insert = function (num) {
        heap.push(num);
        if (heap.length > 2) {
            let idx = heap.length - 1;
            while (heap[idx] < heap[Math.floor(idx / 2)]) {
                if (idx >= 1) {
                    [heap[Math.floor(idx / 2)], heap[idx]] = [heap[idx], heap[Math.floor(idx / 2)]];
                    if (Math.floor(idx / 2) > 1) {
                        idx = Math.floor(idx / 2);
                    } else {
                        break;
                    };
                };
            };
        };
    };

    this.remove = function () {
        const smallest = heap[1];
        if (heap.length > 2) {
            heap[1] = heap[heap.length - 1];
            heap.splice(heap.length - 1);
            if (heap.length == 3) {
                if (heap[1] > heap[2]) {
                    [heap[1], heap[2]] = [heap[2], heap[1]];
                };
                return smallest;
            };
            let i = 1;
            let left = 2 * i;
            let right = 2 * i + 1;
            while (heap[i] >= heap[left] || heap[i] >= heap[right]) {
                if (heap[left] < heap[right]) {
                    [heap[i], heap[left]] = [heap[left], heap[i]];
                    i = 2 * i;
                } else {
                    [heap[i], heap[right]] = [heap[right], heap[i]];
                    i = 2 * i + 1;
                };
                left = 2 * i;
                right = 2 * i + 1;
                if (heap[left] == undefined || heap[right] == undefined) {
                    break;
                };
            };
        } else if (heap.length == 2) {
            heap.splice(1, 1);
        } else {
            return null;
        };
        return smallest;
    };

    this.sort = function () {
        const result = [];
        while (heap.length > 1) {
            result.push(this.remove());
        };
        return result;
    };
};

const minHeap = new MinHeap();

minHeap.insert(1);
minHeap.insert(5);
minHeap.insert(9);
minHeap.insert(10);
minHeap.insert(6);
minHeap.insert(12);

console.log(minHeap.print());