在函数内返回函数vs语句之间的区别

Question

I'm reading Eloquent JS and the example of closures has a code of block that returns a function returning a value. What is the difference between that and returning the value right away.

// returning value 
function wrapValue(n) {
    let local = n;
    return local;
  }

let wrap1 = wrapValue(1);
let wrap2 = wrapValue(2);
console.log(wrap1);
// → 1
console.log(wrap2);
// → 2

// returning a value with a function
function wrapValue2(n) {
    let local = n;
    return () => local;
  }

let wrap3 = wrapValue2(3);
let wrap4 = wrapValue2(4);
console.log(wrap3());
// → 3
console.log(wrap4());
// → 4

Answer 1

For the purpose of just logging the same value without doing anything else to it, there is absolutely no difference whatsoever.

But there are scenarios where you have to do some other operation later on upon returning the value like so

 function doubleTheValue(n){ const val = n * 2; return () => val * 2; } const doubleValueAgain = doubleTheValue(2); console.log(doubleValueAgain()); 

So to answer your question, if you try to return a function instead of just the value, then you have to call the returned result again just to get the value.