Jsfiddle is mainly made to test javascript code in a web context (aka with HTML and CSS). But, if you just want to use is to test backend code, you probably want to see results in the console. This can be done by adding the following library to your project :
https://rawgit.com/eu81273/jsfiddle-console/master/console.js
You can also take a look at this example :
https://jsfiddle.net/p24wbehf/1/
https://rawgit.com/eu81273/jsfiddle-console/master/console.js
You can also take a look at this example :
https://jsfiddle.net/p24wbehf/1/