Use Destructuring Assignment to Pass an Object as a Function's Parameters question

JavaScript
1

I saw this code from an old post. (link:Use Destructuring Assignment to Pass an Object as a Function Parameters)
I also don’t understand why we had to return an identical function inside a function. I tried a different code below this code and it works fine. (read till the end before replying please) Can someone explain the point of having a function inside a function?

const stats = {
  max: 56.78,
  standard_deviation: 4.34,
  median: 34.54,
  mode: 23.87,
  min: -0.75,
  average: 35.85
};
const half = (function() {
  "use strict"; // do not change this line

  // change code below this line
  return function half({max,min}) {
    // use function argument destructuring
  return (max + min) / 2.0;
  };
  // change code above this line

})();
console.log(stats); // should be object
console.log(half(stats)); // should be 28.015

I tried the code below and it also works

const stats = {
  max: 56.78,
  standard_deviation: 4.34,
  median: 34.54,
  mode: 23.87,
  min: -0.75,
  average: 35.85
};
const half = ({max,min}) => {
    // use function argument destructuring
  return (max + min) / 2.0;
  };
  // change code above this line


console.log(stats); // should be object
console.log(half(stats)); // should be 28.015
2

In this case the purpose was to enforce "use strict", I guess for students to use proper syntax and good conventions :slight_smile:

To me it makes no sense and actually demonstrates bad conventions of naming and using same names for variables from outer scope, known as variable shadowing

3

the challenge has been changed, so you don’t need this complex thing to complete the challenge now

4

Continuing the discussion from Use Destructuring Assignment to Pass an Object as a Function's Parameters question:

To me I see this as a recursion where the an anonymous function was assigned to the variable half an immediately it was called to pass in the parameters and the statements. In otherwords without recursion it would have been;

> const half = function(){"use strict"};

after assigning the anonymous function the name of half then we say;

> function half({max, min}) {
>        return (max + min) / 2.0;
>      };

> console.log(half(stats));

//28.015

That is how is understand the attempt above unless there is another use apart from recursion.

5

It’s not recursion, it’s just a function that returns a function. Recursion is when a function calls itself, ie

function niceFunction() {
  return niceFunction();
}
6

Sorry, I don’t follow, could you explain further? How can using a function to return a function enforce strict mode?

7

previously strict mode couldn’t be used in the global scope, so it was put in these functions that return an other function.
now strict mode is enforced in the background, this issue of needing to create the environment on where it is enforced is no more present