How to check if a KeyboardEvent object is in JavaScript?

Question

I want to have a function that takes an event as a parameter and checks if a valid event object has passed.

function doSomething(e){
  if(e is a keyboard event){
   // Proceed
  } else {
    console.log('Error: e is not a KeyboardEvent');
  }
}

typeof ejust returns object. But the debug console shows KeyboardEvent clearly, so you need to read it somehow.

Answer 1

as simple as with an operator instanceof:

if (e instanceof KeyboardEvent){
  // it is a keyboard event!
}

Explanations from MDN :

The operator instanceofchecks to see if the object in its prototype chain has the prototype property of the constructor.

, (i) /, . / .

Answer 2

if(e.type == 'keypress')

function doSomething(e){
  if(e.type == 'keypress'){
   // Proceed
  } else {
    console.log('Error: e is not a KeyboardEvent');
  }
}

Answer 3

This will work for your business.

Be careful with input-eventthis, this is not an instance of KeyboardEvent.

function testEventType(e){
	console.log(e.type, e instanceof KeyboardEvent);
}

document.querySelector("#test").addEventListener('keypress', testEventType);
document.querySelector("#test").addEventListener('input', testEventType);

<input id="test"/>

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