gistfile1.js

'use strict';

var arr = [ 1, 2, 3, 4, 5 ];
var fnArr = [];

// Wrong 1
for (var i = 0; i < arr.length; i++) {
  fnArr[i] = function() {
    return arr[i];
  };
}

fnArr.forEach(function(fn) {
  console.log(fn());
});
// undefined * 5

// Wrong 2
for (var i = 0; i < arr.length; i++) {
  var curr = arr[i];
  fnArr[i] = function() {
    return curr;
  };
}

fnArr.forEach(function(fn) {
  console.log(fn());
});
// 5 * 5

// Solution 1
for (var i = 0; i < arr.length; i++) {
  fnArr[i] = (function(ii) {
    return function() {
      return arr[ii];
    };
  })(i);
}

fnArr.forEach(function(fn) {
  console.log(fn());
});
// 1 2 3 4 5

// Solution 2 - ECMAScript 5
arr.forEach(function(row, i) {
  fnArr[i] = function() {
    return row;
  };
});

fnArr.forEach(function(fn) {
  console.log(fn());
});
// 1 2 3 4 5

// Solution 3 - Harmony
for (var i = 0; i < arr.length; i++) {
  let curr = arr[i];
  fnArr[i] = function() {
    return curr;
  };
}
fnArr.forEach(function(fn) {
  console.log(fn());
});
// 1 2 3 4 5