Run results for: pure mergeSort - vs - memoized mergeSort

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36

Browser: Chrome 126

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
pure	86.5 Ops/sec
memoized	671.7 Ops/sec

Script Preparation code:

function mergeSort(arr) {
    if (arr.length < 2) {
        return arr;
    }

    const midIndex = Math.floor(arr.length / 2);
    const left = mergeSort(arr.slice(0, midIndex));
    const right = mergeSort(arr.slice(midIndex));
    const result = [];

    while (left.length && right.length) {
        if (left[0] < right[0]) {
            result.push(left.shift());
        } else {
            result.push(right.shift());
        }
    }

    return [...result, ...left, ...right];
}

function memoize(fn) {
    const storage = {};

    return function(...args) {
        const key = JSON.stringify(args);

        if (key in storage) {
            return storage[key];
        } else {
            const result = fn(...args);
            storage[key] = result;
            return result;
        }
    }
}

var memoizedMergeSort = memoize(mergeSort);

var array = [...Array(1000)].map(() => Math.random());

Tests:

pure
[...Array(10)].forEach(() => { mergeSort(array); });
memoized
[...Array(10)].forEach(() => { memoizedMergeSort(array); });