A for-of loop, introduced in ES6, is a great way to iterate over an array:

for (const v of ['a', 'b', 'c']) {
  console.log(v)
}

How can you get the index of an iteration?

The loop does not offer any syntax to do this, but you can combine the destructuring syntax introduced in ES6 with calling the entries() method on the array:

for (const [i, v] of ['a', 'b', 'c'].entries()) {
  console.log(i, v)
}