for...of, syntax for (variable of iterable) { statement }

Iterating over an Array:

let iterable1 = [10, 20, 30];

for (let value of iterable1) {
  value += 1;
  console.log(value);
}
// 11
// 21
// 31

let iterable2 = [10, 20, 30];

for (const value of iterable2) {
// no, no:  value += 1;
  console.log(value);
}
// 10
// 20
// 30

Iterating over a Set and over arguments object:

let iterable = new Set([1, 1, 2, 2, 3, 3]);
for (let value of iterable) {
  console.log(value);
}
// 1
// 2
// 3

(function() {
  for (let argument of arguments) {
    console.log(argument);
  }
})(1, 2, 3);

// 1
// 2
// 3

Iterating over a Map:

let iterable5 = new Map([['a', 1], ['b', 2], ['c', 3]]);

for (let entry of iterable5) {
  console.log(entry);
}
// ['a', 1]
// ['b', 2]
// ['c', 3]

for (let [key, value] of iterable5) {
  console.log(value);
}
// 1
// 2
// 3