[nailer]

Shouldn't the answer be obvious?

Every Python tutorial: type 'python' and enter commands into the REPL.

Every Ruby tutorial: type 'ruby' and enter commands into the REPL.

Every Exlixir tutorial: type 'iex' and enter commands into the REPL.

Every Perl tutorial: type 'perl' and enter commands into the REPL.

So for JavaScript: type 'node' and enter commands into the REPL.

[michalskop]

Shouldn't the next question be obvious? - "What is a REPL?"

[canes123456]

Also, doing things in a REPL usually pretty different.