Icons with .js extension
Its pretty easy, here's how you do it:


First of all select your folder/file in Finder, then right click on it and select Get Info.
In the info panel, click on folder/file preview in the top left corner. 
Now, when the preview is highlighted, hit backspace ( ← ) on your keyboard.
Done!


If you cant select that .js than do the same thing to a different .js