Le 11/06/2012 15:13, Hemanth H.M a écrit :
Uber kool! Thanks a ton David!
|npm install es6-shim # wow :) Shall blog about this!
|
Well, Map() and Set() is already there is FF13, it's
an experimental API right? Experimental means it can be chucked off or
it shall be modified drastically ? ( More Java like APIs :\ )
Well {} behaved liked map and well for sets we can use
[].sort.filter(function(v,i,o){return v!==o[i-1];}
The major use case for Maps and Sets (as far as i'm concerned) is the
ability to use objects as keys. Having built-in implementation of these
potentially enable O(1)-ish lookups (which is impossible to implement in
JavaScript).
As to Maps and {} being equivalent, that's true expect when it's not,
like when you want to use pseudo properties like __proto__ or
__noSuchMethod__ as keys. Some folks tried to use objects as maps and
got burned [1]. See Caja's StringMap [2] for a workaround when you only
need strings as keys.
David
[1] http://productforums.google.com/forum/#!topic/docs/0hQWeOvCcHU
[2]
http://code.google.com/p/google-caja/source/browse/trunk/src/com/google/caja/ses/StringMap.js
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