Is there a mechanism to loop x times in ES6 (ECMAScript 6) without mutable variables?

Question

The typical way to loop x times in JavaScript is:

for (var i = 0; i < x; i++)
  doStuff(i);

But I don't want to use the ++ operator or have any mutable variables at all. So is there a way, in ES6, to loop x times another way? I love Ruby's mechanism:

x.times do |i|
  do_stuff(i)
end

Anything similar in JavaScript/ES6? I could kind of cheat and make my own generator:

function* times(x) {
  for (var i = 0; i < x; i++)
    yield i;
}

for (var i of times(5)) {
  console.log(i);
}

Of course I'm still using i++. At least it's out of sight :), but I'm hoping there's a better mechanism in ES6.

Answer 1

Using the ES2015 Spread operator:

[...Array(n)].map()

const res = [...Array(10)].map((_, i) => {
  return i * 10;
});

// as a one liner
const res = [...Array(10)].map((_, i) => i * 10);

Or if you don't need the result:

[...Array(10)].forEach((_, i) => {
  console.log(i);
});

// as a one liner
[...Array(10)].forEach((_, i) => console.log(i));

Or using the ES2015 Array.from operator:

Array.from(...)

const res = Array.from(Array(10)).map((_, i) => {
  return i * 10;
});

// as a one liner
const res = Array.from(Array(10)).map((_, i) => i * 10);

---

Note that if you just need a string repeated you can use String.prototype.repeat.

console.log("0".repeat(10))
// 0000000000