Clarification on the Difference Between Two Ways of Calling a Function in JavaScript

Question

I am a little confused about the way function is called in these cases

onPress(() => myFunction()) And onPress(myFunction) Is it the same thing but the 2nd one is a shortened version of the first one?

Answer 1

Both onPress(() => myFunction()) and onPress(myFunction) will call the myFunction function when the onPress event occurs.

The first example, onPress(() => myFunction()), uses an arrow function as a wrapper to call myFunction. The arrow function is an anonymous function that immediately calls myFunction when executed. This is useful if you need to pass arguments to myFunction or if you need to perform some additional operations before calling myFunction.

The second example, onPress(myFunction), directly passes the myFunction function as an argument to the onPress event handler. This is a shorter and simpler way to call the function if you don't need to do anything else before calling myFunction.

In short, the second example is a shortened version of the first one, but they both accomplish the same thing.

Example of additional operations before calling myFunction:

Imagine you have a button component in a React application and you want to log a message to the console when the button is pressed. In addition to logging the message, you also want to perform some other operation, such as incrementing a counter.

You could achieve this using an arrow function as follows:

const MyButton = () => {
  let counter = 0;

  const handleButtonPress = () => {
    console.log('Button pressed!');
    counter++;
  };

  return (
    <button onClick={() => handleButtonPress()}>
      Click me
    </button>
  );
};