Update free-programming-playgrounds.md (#8119)

* Update free-programming-playgrounds.md

* fix lint error

more/free-programming-playgrounds.md

@@ -172,6 +172,7 @@
 * [InterviewBit - Online JavaScript Compiler IDE](https://www.interviewbit.com/online-javascript-compiler/)
 * [JSBin](https://jsbin.com)
 * [JSFiddle](https://jsfiddle.net)
+* [OneCompiler](https://onecompiler.com/javascript)
 * [Plunker](https://plnkr.co)
 * [SoloLearn](https://code.sololearn.com/web#javascript)