v8-devtools-bug

test2.js

// Run it here: https://jsfiddle.net/billhance/wfz9fcs6/1/
const selectionSortSlow = arr => {
    let curr = 0;
    let n = arr.length;
    while (curr < n) {
        let low = curr;
        let next = curr + 1;
        while (next < n) {
            if (arr[next] > arr[low]) {
                low = next;
            }
            next++;
        }
        // tmp is declared inside the outer loop
        let tmp = arr[curr];
        arr[curr] = arr[low];
        arr[low] = tmp;
        curr++;
    }
};

const selectionSortFast = arr => {
    let curr = 0;
    let n = arr.length;
    // tmp is declared outside of the loop
    let tmp = null;
    while (curr < n) {
        let low = curr;
        let next = curr + 1;
        while (next < n) {
            if (arr[next] > arr[low]) {
                low = next;
            }
            next++;
        }
        tmp = arr[curr];
        arr[curr] = arr[low];
        arr[low] = tmp;
        curr++;
    }
};

const selectionSortFastest = arr => {
    let curr = 0;
    let n = arr.length;
    while (curr < n) {
        let low = curr;
        let next = curr + 1;
        while (next < n) {
            if (arr[next] > arr[low]) {
                low = next;
            }
            next++;
        }
        // Wrap the swap with arbitrary block scoping
        {
            let tmp = arr[curr];
            arr[curr] = arr[low];
            arr[low] = tmp;
            curr++;
        }
    }
};

console.profile("selectionSortSlow");
selectionSortSlow([...Array(10000).keys()]);
console.profileEnd();

console.profile("selectionSortFast");
selectionSortFast([...Array(10000).keys()]);
console.profileEnd();

console.profile("selectionSortFastest");
selectionSortFastest([...Array(10000).keys()]);
console.profileEnd();