On Wed, May 11, 2011 at 11:16, David Bruant <[email protected]> wrote: > A memoizer could be written to improve f time performance (by the cost of > memory, of course). > ---- > function memoizer(f){ > var cache = WeakMap(); > return function(o){ > var res; > if(WeakMap.has(o)) > return cache.get(o); > res = f.apply(this, o); > > cache.set(o, res); > }; > } > ----
I'm not sure I understand your code. it's not clear to me why you need .has at all, since you can check the return value of .get instead. in the case where 'undefined' is a valid value that you would want to memoize, you can store a unique object to represent 'undefined'. also, memoization is usually caching on argument values rather than argument identity, but weakmap lookups are by object identity not object value. You can't use non-object keys in a weekmap, so in order to gain the benefits of the memoization above, a caller would have to be careful to avoid constructing new objects with the same values, and somehow keep re-using the same argument objects, which is pretty inconvenient for typical uses of memoization. _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
