The Complete React Developer Course (with Hooks and Redux) - ES6 Promises

The video tutorial introduces JavaScript promises, explaining their role in handling asynchronous tasks. It covers creating and using promises, simulating delays with setTimeout, and handling multiple callbacks. The tutorial also discusses promise resolution and rejection, and explores alternatives to promise syntax. The focus is on practical examples, particularly in the context of Firebase, to demonstrate how promises can manage asynchronous operations effectively.

What is the primary purpose of promises in JavaScript?

• To create new JavaScript objects

• To manage asynchronous tasks

• To simplify CSS styling

• To handle synchronous operations

Which function is used to create a new promise in JavaScript?

• createPromise()

• Promise.new()

• Promise.create()

• new Promise()

What does the resolve function do in a promise?

• It retries the promise

• It logs an error message

• It indicates a successful operation

• It cancels the promise

How can you simulate a delay in a promise resolution?

• Using setImmediate

• Using clearTimeout

• Using setTimeout

• Using setInterval

What method is used to handle a promise rejection?

• .then()

• .reject()

• .finally()

• .catch()

What happens if a promise is rejected and there is no catch handler?

• A JavaScript error is thrown

• The promise is ignored

• The promise retries

• The promise resolves automatically

Which method can take two arguments to handle both resolve and reject cases?

• .finally()

• .catch()

• .then()

• .resolve()

What is a key limitation of a promise in terms of resolve and reject?

• A promise can only be resolved or rejected once

• A promise can be rejected multiple times

• A promise can be resolved multiple times

• A promise can be both resolved and rejected

What should you do if you need to pass multiple pieces of data in a promise?

• Pass them as a string

• Use an array

• Pass them as separate arguments

• Use an object

What is the typical use case for promises in libraries like Firebase?

• To manage user authentication

• To style web pages

• To handle asynchronous data operations

• To create new databases