That's similar to the Labeler proposed by Mark, except it needs to search for the thing twice (wm.has + wm.get instead of just wm.get which would be just fine as check if you count from 1 instead of 0 ;-) )
Although I need to understand if you have a wm why wouldn't you just use that instead of a Symbol ... so the Labeler seems again a more appropriate pattern for this problem. Just my thoughts On Wed, Sep 9, 2015 at 10:51 AM, Michał Wadas <[email protected]> wrote: > Following solution will work: > > (function(){ > const wm = new WeakMap(); > Symbol.identity = Symbol( 'Symbol.identity' ); > let i = 0; > Object.defineProperty( > Object.prototype, > Symbol.identity, > { > get: function () { > if (wm.has(this)) return wm.get(this); > wm.set(this, Symbol(i++)); > return wm.get(this); > } > } > ); > })() > > > 2015-09-08 23:29 GMT+02:00 Andrea Giammarchi <[email protected]> > : > >> as side note, that's just a lazy assignment that doesn't need two symbols >> and a constant get invoke ... >> >> ```js >> Symbol.identity = Symbol( 'Symbol.identity' ); >> var OBJECT_ID = 0; >> Object.defineProperty( >> Object.prototype, >> Symbol.identity, >> { >> get: function () { >> // first time this is invoked ... and no more ... >> Object.defineProperty(this, Symbol.identity, {value: ++OBJECT_ID}); >> // from now own, direct property access \m/ >> return this[Symbol.identity]; >> } >> } >> ); >> ``` >> >> Regards >> >> On Tue, Sep 8, 2015 at 9:57 PM, Michael McGlothlin < >> [email protected]> wrote: >> >>> I try to keep it pretty simple. It's not fancy but the times you want >>> fast and dirty information like this are the same times you don't want to >>> have to define it manually. >>> >>> Symbol.identity = Symbol( 'Symbol.identity' ); >>> const identity = Symbol( 'identity' ); >>> var OBJECT_ID = 0; >>> Object.defineProperty( Object.prototype, Symbol.identity, { >>> get: () => { >>> if ( !Object.hasOwnProperty.call( this, identity ) ) { >>> this[ identity ] = ++OBJECT_ID; >>> } >>> return this[ identity ]; >>> } >>> } ); >>> >>> On Tue, Sep 8, 2015 at 1:44 PM, Mark S. Miller <[email protected]> >>> wrote: >>> >>>> See Labeler at >>>> http://wiki.ecmascript.org/doku.php?id=harmony:weak_maps#unique_labeler >>>> >>>> >>>> >>>> On Tue, Sep 8, 2015 at 11:16 AM, joe <[email protected]> wrote: >>>> >>>>> Didn't send to list, something is wrong with my reply all. Sorry about >>>>> that. Stupid mobile gmail. >>>>> ---------- Forwarded message ---------- >>>>> From: "joe" <[email protected]> >>>>> Date: Sep 8, 2015 11:15 AM >>>>> Subject: Re: Object id, hash, etc? >>>>> To: "Garrett Smith" <[email protected]> >>>>> Cc: >>>>> >>>>> I agree with this request. This is the logical complement to valueof, >>>>> I think. And yes, for most ID use cases this isn't a good fit, but we're >>>>> not talking about the general case, just the cases where a python style >>>>> id() function *is* appropriate. >>>>> >>>>> Joe >>>>> On Sep 8, 2015 9:08 AM, "Garrett Smith" <[email protected]> >>>>> wrote: >>>>> >>>>>> On 9/8/15, Michael McGlothlin <[email protected]> wrote: >>>>>> > Is there a reason not to provide an object id and hash value as >>>>>> other >>>>>> > languages often do? I find myself defining an identity symbol on >>>>>> objects >>>>>> > with a value from a simple global counter. It makes it easier to >>>>>> debug if I >>>>>> > can just look at a log and see what objects and functions were >>>>>> active. >>>>>> > >>>>>> > Likewise a hash value would simplify a lot of comparisons and make >>>>>> it easier >>>>>> > to debug. >>>>>> > >>>>>> > I especially find the ID useful when working with bound functions >>>>>> as they >>>>>> > can be difficult to tell apart. I like to change toString() to >>>>>> provide the >>>>>> > ID followed by the code (flattened to one line). >>>>>> > >>>>>> > >>>>>> >>>>>> NFE's are safe to use where IE8 support isn't needed*. >>>>>> (function aa(){}).name; // "aa" >>>>>> >>>>>> As for using Object IDs and Object Pooling, lexically-scoped values >>>>>> have benefits over global ID generators (as your counter). The values >>>>>> can be passed in as a parameter to the Factory (useful with Private >>>>>> Proxy). There other benefits to this pattern regarding memory >>>>>> management and application design. Contact me if you'd like to learn >>>>>> more. >>>>>> >>>>>> * https://kangax.github.io/nfe/ >>>>>> -- >>>>>> Garrett >>>>>> @xkit >>>>>> ChordCycles.wordpress.com >>>>>> garretts.github.io >>>>>> personx.tumblr.com >>>>>> _______________________________________________ >>>>>> es-discuss mailing list >>>>>> [email protected] >>>>>> https://mail.mozilla.org/listinfo/es-discuss >>>>>> >>>>> >>>>> _______________________________________________ >>>>> es-discuss mailing list >>>>> [email protected] >>>>> https://mail.mozilla.org/listinfo/es-discuss >>>>> >>>>> >>>> >>>> >>>> -- >>>> Cheers, >>>> --MarkM >>>> >>>> _______________________________________________ >>>> es-discuss mailing list >>>> [email protected] >>>> https://mail.mozilla.org/listinfo/es-discuss >>>> >>>> >>> >>> _______________________________________________ >>> es-discuss mailing list >>> [email protected] >>> https://mail.mozilla.org/listinfo/es-discuss >>> >>> >> >> _______________________________________________ >> es-discuss mailing list >> [email protected] >> https://mail.mozilla.org/listinfo/es-discuss >> >> >
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