Q
How can you ensure that a callback runs only once, even if the promise is resolved multiple times?

Answer & Solution

Answer: Option D
Solution:
The then() method ensures that a callback runs only once, even if the promise is resolved multiple times, by handling both success and failure cases appropriately.
Related Questions on Average

What is a deferred object in jQuery?

A). An object that stores HTML elements

B). An object that represents a task that will finish in the future

C). An object that handles CSS styles

D). An object that manages event listeners

What is event delegation in jQuery?

A). Attaching event handlers to dynamically created elements

B). Attaching event handlers to static elements

C). Attaching event handlers to parent elements

D). Attaching event handlers to all elements

Which jQuery method is used to handle both success and failure cases of a promise?

A). done()

B). fail()

C). always()

D). then()

How do you attach multiple callbacks to a jQuery promise?

A). Using multiple then() methods

B). Using multiple done() methods

C). Using multiple fail() methods

D). Using multiple always() methods

What does the promise() method return in jQuery?

A). A new deferred object

B). A new promise object

C). A new callback function

D). A new event handler

Which method allows you to specify multiple callbacks for different outcomes of a promise in jQuery?

A). done()

B). fail()

C). always()

D). then()

What is the purpose of the done() method in jQuery promises?

A). To handle failed operations

B). To handle completed operations

C). To handle pending operations

D). To create a new deferred object

How does event delegation handle dynamically added elements?

A). By re-attaching event handlers

B). By attaching event handlers to the parent element

C). By using the .bind() method

D). By using the .on() method with a selector

Which method is used to define custom validation rules in jQuery?

A). validateRule()

B). addRule()

C). addMethod()

D). validateMethod()

What does the fail() method do in jQuery promises?

A). Attaches a callback for when the promise is rejected

B). Attaches a callback for when the promise is resolved

C). Attaches a callback for when the promise is pending

D). Attaches a callback for when the promise is created