How to display the elements of a function / array of the form a[index]() without redefining the identifier?

Question

JavaScript

var a = [1,2,3,77,5,6];
var b = [];

for (var i in a){
    b.push(a[i]);
    a[i] = function() {
        return b[i];
    }
}

for (var i in a){
    console.log(a[i]())
}

When the function is called, the entire list of the array is displayed on the console, but this is due to the redefinition of the identifier. Please tell me what needs to be done so that when console.log(a[3]())(the construction must be of this type) 77 is displayed on the screen, and not the last element in the array?

Answer 1

The variable i is lost in the closure .
I'll try to describe in words.
In your case, at the time a[3]() is called , i has the last value in the loop.
Accordingly, I applied an IIFE to store the value of i by creating a new context.
DEMO

'use strict';

var a = [1,2,3,77,5,6];
var b = [];

for (var i in a) {
    b.push(a[i]);
    
    a[i] = (function(i) {
      return function() {
        return b[i];
      };
    })(i);
}

console.log(a[3]());