IterableIteratorの挙動テスト。

iterable-iterator-test.js

function* gen() {
    let i = 0;
    while(true) {
        yield i++;
    }
}

const g1 = gen();
console.log(g1.next()); // { value: 0, done: false }

const g2 = g1[Symbol.iterator]();
console.log(g2.next()); // { value: 1, done: false }

const g3 = g2[Symbol.iterator]();
console.log(g3.next()); // { value: 2, done: false }

const g4 = g1[Symbol.iterator]();
console.log(g4.next()); // { value: 3, done: false }

console.log(g1 === g1[Symbol.iterator]()); // true

const g5 = g1[Symbol.iterator]()[Symbol.iterator]();
console.log(g5.next()); // { value: 4, done: false }

const g6 = gen();
console.log(g6.next()); // { value: 0, done: false }

console.log(gen() === gen()); // false