Simple sets in JavaScript
One of my favourite JavaScript features is its literal object notation.
It allows you to declare data structures in JSON, which is a very
succinct, C-like syntax. You can use this notation to declare SETs, and
the a in b syntax to verify a variable is in a set:
/* Declare your set as a JSON constant */
var valid_widgets = {
'widget-viewer': 1,
'special-viewer': 1,
'widget-editor': 1
};
/* Fail if something isn't in the set */
if ( ! (options.widget in valid_widgets) )
return false;
/* Profit! */
As the in keyword operates on the index of the referred object, we set
the value of the constants to 1 (true). A bit of a hack, but it
results in a very clean way of checking if something is part of a set of
valid values.