JavaScript Quiz: Iterators

How to iterate over an array with a classic for-loop?

let arr = ["a", "b", "c"];

for (let i = 0; i < arr.length; i++) {
    console.log(arr[i]);
}

How to iterate over an array with an "enhanced" for-loop?

let arr = ["a", "b", "c"];

for (let elem of arr) {
    console.log(elem);
}

How to iterate over an array by passing a function for element processing?

let arr = ["a", "b", "c"];

arr.forEach((value, index) => console.log(`${index}: ${value}`));

How to create an iterator over the values from 3 to 5?

// this is a generator function;
// note the asterisk "*" after the "function" keyword:
function* createIterator() {

    yield 3;
    yield 4;
    yield 5;

    /* alternative #1: 
    for (let i = 3; i <= 5; i++) {
        yield i;
    }
    */

    /* alternative #2:
    // note the asterisk here, making yield iterate over its operand:
    yield* [3, 4, 5];
    */
}

let iter = createIterator();
for (let elem of iter) {
    console.log(elem);
    // output:
    // 3
    // 4
    // 5
}