You don't have to use all the syntax sugar, eg. array.concat vs ...spread And I guess its hard to stop thinking about types. its probably easier to go from assembly to JS, then from Java to JS ... In JS you just have to know string or number ... Although I'm no fan of it, you can annotate the variables like sName, nAge, sAddress, nCount, nId, sComment, nCommentId, etc. Or use - - (minus minus) when doing addition. Most other bugs will result in syntax errors or the classic "undefied is not a function" when trying to call push on an object that is not an array object.