generators.js

// ES6 Generators
// @See: https://medium.com/dailyjs/a-simple-guide-to-understanding-javascript-es6-generators-d1c350551950

function* gChild() { 
    yield 2;
    yield 3;
}

function* gMain() { 
    yield 1;
    yield* gChild();
    yield 4;
}

let generator = gMain();

// console.log(generator.next()); // { value: 1, done: false }
// console.log(generator.next()); // { value: 2, done: false }
// console.log(generator.next()); // { value: 3, done: false }
// console.log(generator.next()); // { value: 4, done: false }
// console.log(generator.next()); // { value: undefined, done: true }

// or
for (const iterator of generator) {
    console.log(iterator); // 1, 2, 3, 4
}