iterate iterator (created from generator function) in for-of/while/for loops

iterate.js

function* generatorFunction() {
    // ...
}
let iterator = generatorFunction();

// for-of loop
for (let k of iterator) {
    // ...
}

// equivalent for loop
let i, k;
while (!(i = iterator.next()).done) {
    k = i.value;
    // ...
}