for with index in js code example

Example 1: javascript for...of index

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

Example 2: javascript enumerate with index

const iterable = [...];
for (const [index, elem] in iterable.entries()) {
  f(index, elem);
}

// or
iterable.forEach((elem, index) => {
  f(index, elem);
});