```js
// 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
.tabOpen() // Open a new tab for cat memes
.join(videoWindow.tabClose(2)) // Close third tab in video window, and join
.join(workWindow.tabClose(1).tabOpen());
alert(finalTabs.tabs);
```
## Solution