JavaScript's For-Of Loops Are Fast(waspdev.com)

    Why? This enforces our immutable rule. Dealing with pure functions that return values is easier to reason about than side effects.

    // bad
    let sum = 0;
    for (let num of numbers) {
      sum += num;
    }
    sum === 15;

    // good
    let sum = 0;
    numbers.forEach((num) => {
      sum += num;
    });
    sum === 15;