SliceVsSpreadOperator.js

function test(iterations) {
    console.log(`Testing with ${iterations} iterations`);
    const originalArray = [];

    console.time('data');
    for (let i = 0; i < 1000; i++) {
        originalArray.push(i);
    }
    console.timeEnd('data');

    console.time('slice');
    let sliceTmp;
    for (let i = 0; i < iterations; i++) {
        sliceTmp = originalArray.slice(0);
    }
    console.timeEnd('slice');

    console.time('spread');
    let spreadTmp;
    for (let i = 0; i < iterations; i++) {
        spreadTmp = [...originalArray];
    }
    console.timeEnd('spread');
}

test(1);
test(10);
test(100);
test(1000);
test(10000);
test(100000);
test(1000000);

// OUTPUT

> Testing with 1 iterations
> data: 0.084ms
> slice: 0.413ms
> spread: 0.48ms

> Testing with 10 iterations
> data: 0.0859ms
> slice: 0.217ms
> spread: 2.91ms

> Testing with 100 iterations
> data: 0.075ms
> slice: 5.86ms
> spread: 33.3ms

> Testing with 1000 iterations
> data: 0.05ms
> slice: 25.1ms
> spread: 159ms

> Testing with 10000 iterations
> data: 0.0261ms
> slice: 21.2ms
> spread: 1230ms

> Testing with 100000 iterations
> data: 0.0259ms
> slice: 125ms
> spread: 12000ms

> Testing with 1000000 iterations
> data: 0.0352ms
> slice: 1200ms
> spread: 120000ms