Promises in JavaScript

The video tutorial explains the concept of promises in JavaScript, highlighting their importance in handling asynchronous operations. It covers basic examples, including chaining promises and handling errors. The tutorial concludes with a real-world application, demonstrating how promises are used in a web service to fetch data asynchronously.

Why are promises used in JavaScript?

• To handle synchronous operations

• To improve code readability

• To manage unpredictable asynchronous tasks

• To replace all callbacks

What are the two main parts of a promise?

• Producing code and consuming code

• Promise creation and promise resolution

• Synchronous code and asynchronous code

• Error handling and success handling

What happens when a promise resolves?

• The producing code runs again

• The consuming code executes

• The promise is rejected

• The promise is deleted

How do chained consuming functions behave when a promise resolves?

• They do not run at all

• They run one after another immediately

• They run with a delay between each

• They run only if the promise is rejected

What function is used to handle errors in promises?

• Finally

• Resolve

• Reject

• Catch

What indicates an error in the console when a promise is rejected?

• A green check mark

• A blue info icon

• A red error symbol

• A yellow warning sign

In the real-world example, what does the fetch promise do?

• It synchronously retrieves data

• It waits for a response from the API

• It immediately returns a static value

• It logs an error message

What is the purpose of the 'then' method in a promise?

• To create a new promise

• To cancel the promise

• To handle promise rejection

• To execute code after the promise resolves

Why was an alternative notation used for accessing JSON data in the example?

• The JSON keys contained spaces

• The JSON data was encrypted

• The JSON data was incomplete

• The JSON data was too large

What is the main advantage of using promises in asynchronous operations?

• They make the code run faster

• They eliminate the need for any callbacks

• They simplify error handling

• They allow for cleaner and more manageable code