What Is Plunker? Why Use It?

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Plunker is an online Code Editor which supports HTML5 language.
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http://code-love.com/2014/09/09/plunker/ noted that:

The creator, Geoff Goodman, is a programmer by calling, but not by profession. He works for one of the largest accounting firms in the world, but his true passion is building web technologies.
By day, you’ll see him plugging away at financial models for the sake of profit. At night, he’ll be driven to build things for the sake of passion.

He recently came across a pain point of his that needed solving. He had been using JSFiddle to help sandbox and prototype several versions of his code, but found that it was lacking for more complex Javascript frameworks such as Angular.js, which require more of a file-by-file approach where you can separate out different aspects of your code into a contained and organized multi-file system.
Geoff had been looking to build a timesheet application, but was frustrated by how JSFiddle’s sandbox couldn’t take on the more modern and complex Javascript frameworks that were required to make the application truly interactive.

So he set out and modified the Ace text editor, an open-source code-editor used by Cloud9 to help programmers build and prototype applications in the cloud.

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https://prashantbrall.wordpress.com/2014/08/31/angularjs-and-plunker/ noted that Plunker is very useful for editing AngularJS codes since it allows multiple files creation within a single project.

Plunker or plnkr is an integrated web development environment and is completely written in AngularJS.The plunkr website also provides us to write plunks(codes) and share it with other developers.

once you click on the launch the editor This is how the editor looks like.

There is also ability to search for popular JavaScript library and refer it in your current plunk.

Another feature I really like is the live preview which is quite handy when you are learning AngularJS as you can see the result of your code change in real-time.

The editor is pretty slick and easy to use and nice to see all the html,css and js file can be accessed from the left pane. There is also the ability to save your plunks online and it can also be download as zip from the top right download icon.