CODEWITHSUNDEEP
javascriptecmascript-6generator
Bonnie
Bonnie

Reputation: 21

Generator usage about yield

My code:

function wrapper(generatorFunction) {
  return function (...args) {
    let generatorObject = generatorFunction(...args);
    generatorObject.next();
    return generatorObject;
  };
}

const wrapped = wrapper(function* () {
  console.log(`First input: ${yield}`);
  return 'DONE';
});

wrapped();

I have a question regarding why the web console isn't printing First input. Although yield returns undefined.

Upvotes: 0

Views: 63

Answers (1)

Pawan Kumar
Pawan Kumar

Reputation: 1533

The first time you do next(), it will execute till the first yield. 

function wrapper(generatorFunction) {
    return function (...args) {
        let generatorObject = generatorFunction(...args);
        generatorObject.next(); // Will Print till yield keyword => First Yield Call
        console.log('About to pass in a value to First Input');
        let done = generatorObject.next(42); // Will Print and Bring the next yielded value => First Input 22
        console.log(done);
        return generatorObject;
    };
}

wrapped = wrapper(function* () {
    console.log('First Yield Call');
    console.log(`First input: ${yield}`);
    return 'DONE';
});

wrapped();

Upvotes: 1

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