Understand the Hazards of Using Imperative Code

JavaScript
1

Tell us what’s happening:

Your code so far


// tabs is an array of titles of each site open within the window
var Window = function(tabs) {
  this.tabs = tabs; // we keep a record of the array inside the object
};

// When you join two windows into one window
Window.prototype.join = function (otherWindow) {
  this.tabs = this.tabs.concat(otherWindow.tabs);
  return this;
};

// When you open a new tab at the end
Window.prototype.tabOpen = function (tab) {
  this.tabs.push('new tab'); // let's open a new tab for now
  return this;
};

// When you close a tab
Window.prototype.tabClose = function (index) {
  var tabsBeforeIndex = this.tabs.splice(0, index); // get the tabs before the tab
  var tabsAfterIndex = this.tabs.splice(index); // get the tabs after the tab

  this.tabs = tabsBeforeIndex.concat(tabsAfterIndex); // join them together 
  return this;
 };

// Let's create three browser windows
var workWindow = new Window(['GMail', 'Inbox', 'Work mail', 'Docs', 'freeCodeCamp']); // Your mailbox, drive, and other work sites
var socialWindow = new Window(['FB', 'Gitter', 'Reddit', 'Twitter', 'Medium']); // Social sites
var videoWindow = new Window(['Netflix', 'YouTube', 'Vimeo', 'Vine']); //  Entertainment sites

// Now perform the tab opening, closing, and other operations
var finalTabs = socialWindow
         Window.prototype.tabOpen("cat memes"); // Open a new tab for cat memes
           Window.prototype.join(videoWindow.tabClose(2)) // Close third tab in video window, and join
                 Window.prototype.join(workWindow.tabClose(1).tabOpen());

alert(finalTabs.tabs);

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.77 Safari/537.36.

Link to the challenge:
https://learn.freecodecamp.org/javascript-algorithms-and-data-structures/functional-programming/understand-the-hazards-of-using-imperative-code/

2

Don’t make any changes in this exercise.

This challenge wants you to understand what is wrong with the code so reset your code and submit it as it is.

3

You are not required to solve this challenge but there is a solution.

Three windows are opened with some named tabs. As the windows are merged some tabs are added and some are closed. When done, things literally do not add up. The number of tabs is different that what should be expected. First you have to find the error in the output then determine which method is failing and why. Once you see it the fix is simple.