@toreda/strong-types/dist/swap/pop.js

Better TypeScript code in fewer lines.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.swapPop = void 0;
/**
 * Remove an array element in O(1) time if element ndx is known.
 * Works only with unordered arrays.
 * @param array
 * @param ndx
 *
 * @category Collections
 */
function swapPop(array, ndx) {
    if (!array.length) {
        // pop always returns a value if the length is greater
        // than zero. This check prevents pop from returning a
        // value of undefined.
        return null;
    }
    if (ndx >= array.length || ndx < 0) {
        return null;
    }
    if (array.length === 1 || ndx === array.length - 1) {
        const result = array.pop();
        if (result === undefined) {
            return null;
        }
        return result;
    }
    // Save the element at ndx in the array to
    // keep it safe while we overwrite the slot.
    const element = array[ndx];
    // Move the last element into ndx slot.
    array[ndx] = array[array.length - 1];
    // Pop the last element off the array
    array.pop();
    return element;
}
exports.swapPop = swapPop;