Nice post :D, congratulations! JS sometimes can be really weird haha. There is a typo in the 10th section, in the code snippets: let func = function ( ) { return { a : 1 } )(); // <- }();

Nice :D Other useful tool here: Regex Visualizer: For know how regex works

Why do you use a character set in this example? String[] str=s.split( "[\\s]+" ); I mean, it is unnecessary in this case... Anyway, I love to see people sharing the regex power :)