vanilla-generator-math-v3.js

function getTwoPlusTwo() {
    return 2 + 2;
}

function* myGeneratorFunction() {
    const sum = yield getTwoPlusTwo();
    console.log("two plus two equals: ", sum);
}

const g = myGeneratorFunction();

console.log("calling next the first time...");
const nextObject = g.next();
const nextValue = nextObject.value;
console.log("next: ", nextObject);
console.log("calling next the second time...");
console.log("next: ", g.next(nextValue));

// calling next the first time...
// next:  { value: 4, done: false }
// calling next the second time...
// two plus two equals:  4
// next:  { value: undefined, done: true }