data-structures-and-algorithms/heapq

import {IndexError} from '@failure-abstraction/error';

import {siftdown} from './core/index.js';

export default function heappop(heap) {
    const x = heap.data;
    const n = x.length;

    if (n === 0) throw new IndexError('heappop');

    const last = n - 1;

    // Swap last leaf and root

    const tmp = x[0];
    x[0] = x[last];
    x[last] = tmp;

    // Sift down the new root

    siftdown(heap.compare, x, 0, last, 0);

    // Return old root

    return x.pop();
}