But this isn't just about hinting on it's own - we want node to blow up if we cause a strict error.

We could presumably add the string arg to where we run everything which will put node intro strict mode "--use_strict" - but then again 'use strict' is more explicit it's just annoying to have to append to each file and if we run everything in strict mode libs might fail in that  regard.

``` sh
ॐ~ $ node --use_strict
> foo = 1
ReferenceError: foo is not defined
    at repl:1:6
    at REPLServer.self.eval (repl.js:110:21)
    at Interface.<anonymous> (repl.js:239:12)
    at Interface.EventEmitter.emit (events.js:95:17)
    at Interface._onLine (readline.js:202:10)
    at Interface._line (readline.js:531:8)
    at Interface._ttyWrite (readline.js:760:14)
    at ReadStream.onkeypress (readline.js:99:10)
    at ReadStream.EventEmitter.emit (events.js:98:17)
    at emitKey (readline.js:1095:12)
>
(^C again to quit)
>
ॐ~ $ node
> foo = 1
1
```