Promises & Callbacks — Series 2

Preview — 3 of 10 questions

What is logged?

javascript

Promise.resolve(5)
  .then((val) => {
    throw new Error('Oops');
  })
  .catch((err) => console.log(err.message));

BAn uncaught Error: Oops

C"Oops"

Dundefined

What is logged?

javascript

Promise.resolve('data')
  .then((val) => console.log(val))
  .finally(() => console.log('Cleanup'))
  .catch((err) => console.log('Error:', err));

A"Cleanup", then "data"

BOnly "Cleanup" is logged

C"data", "Cleanup", "Error: undefined"

D"data", "Cleanup"

What is logged?

javascript

function delay(val) {
  return new Promise((resolve) => setTimeout(() => resolve(val), 10));
}

Promise.resolve(1)
  .then((val) => delay(val + 1))
  .then((val) => console.log(val));

CPromise { 2 }

Dundefined

Answer all 10 questions (7 more), see explanations for every answer, and track your score.