when we write for..of loop how does it internally call symbol.iterator [duplicate]

Question

Consider this code.

let array = [1,2,3,4,5]

for(let elem of array) {
    console.log(elem)
}

Since here, I am not calling anything like array[Symbol.iterator]().since we can only execute function by putting parenthesis after the expression that evaluates its value. here we are just writing for(let elem of array) how does it execute a function named array[Symbol.iterator] ?

Answer 1

You can test it simply enough by replacing [Symbol.iterator] and see what happens:

let array = [1,2,3,4,5]

array[Symbol.iterator] =  function* () {
    yield *['Larry', 'Mo', 'Curley'];
};

for(let elem of array) {
    console.log(elem)
}