First version of the extension

Author: Litee

README.md

@@ -1,2 +1,24 @@
-# prevent-duplicate-tabs-chrome-extension
-Chrome extension that detects when a duplicate tab is opened and activates already existing tab
+# "Prevent Duplicate Tabs" Chrome extension
+
+Chrome extension that detects when a duplicate tab is opened and activates already existing tab.
+
+## How to install
+
+I have not published this extension into Chrome Web Store, so your will need to install extension locally:
+
+1. Clone extension to your machine - e.g. `git clone https://github.com/Litee/prevent-duplicate-tabs-chrome-extension.git`
+1. Look at `background.js` and into `manifest.json`. It is always a good idea to check that code does not do anything suspicious and does not have too many permissions ;)
+1. Open chrome://extensions tab in your Chrome browser
+1. Activate developer mode (required for next step)
+1. Install extension as unpacked
+
+Ping me if you liked this extension and I may consider publishing it into Chrome Web Store.
+
+## TODOs
+
+* Support white lists
+* De-duplicate already opened tabs
+
+## Disclaimers
+
+* Icon made by [Picol](https://www.flaticon.com/authors/picol) from [Flaticon](https://www.flaticon.com/) is licensed by [CC 3.0 BY](http://creativecommons.org/licenses/by/3.0/)

background.js

@@ -0,0 +1,31 @@
+chrome.tabs.onCreated.addListener(newTab => {
+    if (newTab.url) {
+        verifyAndDeduplicate(newTab.id, newTab.url);
+    }
+});
+
+chrome.tabs.onUpdated.addListener((updatedTabId, updateInfo, updatedTab) => {
+    if (updateInfo.url) {
+        verifyAndDeduplicate(updatedTabId, updateInfo.url);
+    }
+});
+
+function verifyAndDeduplicate(currentTabId, currentTabUrl) {
+    chrome.tabs.query({}, tabs => {
+        var duplicateTab = null;
+        tabs.forEach(otherTab => {
+            if (otherTab.id !== currentTabId && otherTab.url === currentTabUrl) {
+                duplicateTab = otherTab;
+            }
+        });
+        if (duplicateTab) {
+            chrome.tabs.update(duplicateTab.id, {
+                "active": true
+            });
+            chrome.windows.update(duplicateTab.windowId, {
+                focused: true
+            })
+            chrome.tabs.remove(currentTabId);
+        }
+    });
+}

icon-128.png

@@ -0,0 +1,20 @@
+{
+    "name": "Prevent Duplicate Tabs",
+    "version": "0.0.1",
+    "manifest_version": 2,
+    "description": "Chrome extension that detects when a duplicate tab is opened and activates already existing tab",
+    "icons": {
+        "16": "icon-16.png",
+        "128": "icon-128.png"
+    },
+    "background": {
+        "scripts": [
+            "background.js"
+        ]
+    },
+    "permissions": ["tabs"],
+    "browser_action": {
+        "default_icon": "icon-16.png",
+        "default_title": "Prevent Duplicate Tabs"
+    }
+}