Which React hook returns a mutable ref object?

What is the output of the following code?

window.alert(null == undefined)

How can you dispatch a synthetic event object?

var demo = true;

console.log(demo+true);

console.log(demo+"xyz");

 The ______ method searches a string for a specified value and returns the position of the match 

To use the animation effect during the resizing of an image, we used the _______ property.

The second element in the useState hook is ______________ .

Which property of an autocomplete widget is used to control the delay before the list of the autocomplete widget appears?

What is the essence of animations in JavaScript?

Which of the following is true about the setTimeout() function in JavaScript?