FAQ: Advanced JSX - Event Listeners in JSX

This community-built FAQ covers the “Event Listeners in JSX” exercise from the lesson “Advanced JSX”.

Paths and Courses
This exercise can be found in the following Codecademy content:

Web Development

Learn ReactJS: Part I

FAQs on the exercise Event Listeners in JSX

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Why are we not calling the function with braces.
it is {functionName} but not {functionName()}. Why?

Because that will call functionName() when the element is initiated and set the handler to whatever the function returns.

So if you make a function like this.

function functionName(){
  return function(){
         alert('hello');
   }
}

That would work, but otherwise you just need to reference the function with functionName not actually call it on runtime with functionName() (unless you have a function within a function like above).

The image doesn’t seem to be changing to a puppy - even after I clicked run solution (see attached).

Aside from the fact that the provided solution doesn’t seem to be working (even after I ran the CA provided solution), I also have a follow up question:

  1. The question “Why don’t we set the event listener attribute value to a function call?” explains that we simply reference the function makeDoggy to avoid calling it on runtime, which makes sense.

But, since function makeDoggy(e) takes e as a parameter, what specifically is being passed to e when we reference the function makeDoggy by using <img src… onClick={makeDoggy}, without passing an argument?

Thanks!