function in ur string

Old friend (and clearly damaged by a career of JavaScript programming) @jakedevine threw this down on twitter a few days ago.


    var Z = "constructor"; 
    Z[Z][Z]("alert('wtfjs!')")();
    // alerts wtfjs!

Ok. So wtf exactly is happening here?


    Z[Z]
    // function String() { [native code] }

    Z[Z][Z]
    // function Function() { [native code] }

AHA! The constructor property of a string is String and the constructor property of String is Function. Makes sense.


    Z[Z][Z]("console.log('new Function accepts string for eval as argument')")();
    // new Function accepts string for eval as argument

Of course. One wonders, as usual, wtf the programmer was up to when he discovered this!