Parameters of returning functions in JavaScript

You can pass parameters to the function calls we have studied. In the following example, the inner function expects a string as a parameter and prints it to the console:

javascriptfunction func() {
  return function(str) {
    return str;
  };
}

The second bracket corresponds to the internal function when called, which means that we pass the desired string to this second bracket:

javascriptfunction func() {
  return function(str) {
    return str;
  };
}

console.log( func()('!') ); // shows '!'

Let's make both the first function take a parameter and the second one. And the result of the call will be the sum of these parameters:

javascriptfunction func(num1) {
  return function(num2) {
    return num1 + num2;
  };
}

console.log( func(1)(2) ); // shows 3