> To "polyfill" an idea I have for DOM, to propose it later, etc.
You can consider something like this depending on your needs: https://gist.github.com/Ginden/03004e52b3d331e236b5256e3b4c08ff On Tue, Oct 24, 2017 at 7:47 PM, /#!/JoePea <[email protected]> wrote: > @Michał > > > But why do you need this? > > To "polyfill" an idea I have for DOM, to propose it later, etc. > > @Logan > > > Why not store your data separately in a WeakMap and rather than > injecting properties onto existing objects? Then you can initialize the > stored data on first access of the data you want. > > I thought about that, it seems like the only way, but was curious to > see about the the during-construction way if possible. > > @Andrea > > But this one doesn't work: > > ```js > window.Element = class extends Element { > constructor() { > super(); > console.log('hello darkness my old friend'); > } > }; > > // then ... > class MyEl extends HTMLElement {} > customElements.define('my-el', MyEl); > > new MyEl; > ``` > > /#!/JoePea > > > On Tue, Oct 24, 2017 at 10:36 AM, Andrea Giammarchi > <[email protected]> wrote: > > I know I'm going to regret this already, but since I've secretly played > with > > polyfills, you can still do this: > > > > ```js > > window.HTMLElement = class extends HTMLElement { > > constructor() { > > super(); > > console.log('hello darkness my old friend'); > > } > > }; > > > > // then ... > > class MyEl extends HTMLElement {} > > customElements.define('my-el', MyEl); > > > > new MyEl; > > ``` > > > > Regards > > > > > > > > On Tue, Oct 24, 2017 at 2:32 PM, Logan Smyth <[email protected]> > wrote: > >> > >> Given that these are constructors that you don't own, adding your own > >> properties to them seems like an overall ugly approach to me. Why not > store > >> your data separately in a WeakMap and rather than injecting properties > onto > >> existing objects? Then you can initialize the stored data on first > access of > >> the data you want. > >> > >> On Tue, Oct 24, 2017 at 10:25 AM, /#!/JoePea <[email protected]> wrote: > >>> > >>> Well, I know I can set accessors on a prototype easily, but what I > >>> mean is, I need each instance of an `Element` to have exactly one > >>> instance of something right after construction during the same > >>> synchronous operation. > >>> > >>> For example, if we have an application with a bunch of pre-existing > >>> Elements that do not extend from any classes of mine, I'd like for the > >>> all to have `foo` properties, so that I can do this: > >>> > >>> ```js > >>> const el = new SomeCustomElementThatWasDefinedCreatedByMe > >>> console.log(el.foo) // it exists and is specific to the instance, not > >>> a prototype property > >>> > >>> // or > >>> > >>> const div = document.createElement('div') > >>> console.log(div.foo) // it exists and is specific to the instance, not > >>> a prototype property > >>> ``` > >>> > >>> Can this be done? > >>> /#!/JoePea > >>> > >>> > >>> On Tue, Oct 24, 2017 at 10:19 AM, /#!/JoePea <[email protected]> wrote: > >>> >> This feels like a problem similar to > >>> >> https://esdiscuss.org/topic/block-scoped-prototype-extensions > >>> > > >>> > @Boris, even if it were scoped, how do we monkey patch a > >>> > *constructor*? By the way, for some reason your link to > >>> > `https://esdiscuss.org/topic/block-scoped-prototype-extensions` > posted > >>> > as `https://esdiscuss.org/topic/block` which is 404. If you can edit > >>> > it it would help others not to stumble on a broken link. > >>> > > >>> >> if that would be possible, then everyone could just monkey patch > >>> >> Object, right? > >>> > > >>> > But everyone can monkey patch the entire class already, aside from > the > >>> > constructor, by modifying the prototype. Obviously if someone returns > >>> > something new from the constructor they might break everything, but > it > >>> > will be completely obvious and people then won't do that. The same > >>> > applies with methods and properties, it is super easy to break entire > >>> > applications monkey patching methods. > >>> > > >>> > --- > >>> > > >>> > So suppose I want to "polyfill" a concept. For example, I want all > >>> > elements to have a new "foo" accessor after they've been constructed. > >>> > Or for example, suppose `HTMLElement.prototype.style` and > >>> > `SVGElement.prototype.style` didn't exist yet. How would I patch > those > >>> > in? > >>> > /#!/JoePea > >>> > > >>> > > >>> > On Tue, Oct 24, 2017 at 10:07 AM, Michał Wadas < > [email protected]> > >>> > wrote: > >>> >> AFAIR DOM classes are not extensible by any means. > >>> >> > >>> >> > >>> >> > >>> >> On 24 Oct 2017 6:51 pm, "/#!/JoePea" <[email protected]> wrote: > >>> >>> > >>> >>> Is it possible to monkey-patch an intermediate constructor of a > >>> >>> built-in > >>> >>> subclass? > >>> >>> > >>> >>> For example, suppose I want all `Element` instances in a web app to > >>> >>> have > >>> >>> new instance properties, is there a way to monkey-patch the Element > >>> >>> constructor so that when I make a custom element by extending a > >>> >>> subclass of > >>> >>> `Element` that the new logic will fire? > >>> >>> > >>> >>> For example: > >>> >>> > >>> >>> ```js > >>> >>> // monkey-patch the Element constructor somehow so that it logs > >>> >>> "patched > >>> >>> in Element". > >>> >>> > >>> >>> // then > >>> >>> class FooBar extends HTMLElement {} > >>> >>> customElement.define('foo-bar', FooBar) > >>> >>> new FooBar // "patched in Element" > >>> >>> ``` > >>> >>> > >>> >>> I tried > >>> >>> > >>> >>> ```js > >>> >>> const OldElement = window.Element > >>> >>> > >>> >>> window.Element = function Element() { > >>> >>> const _this = new OldElement > >>> >>> console.log("patched in Element") > >>> >>> return _this > >>> >>> } > >>> >>> > >>> >>> window.Element.prototype = OldElement.prototype > >>> >>> window.Element.prototype.constructor = window.Element > >>> >>> > >>> >>> class FooBar extends HTMLElement {} > >>> >>> customElements.define('f-b', FooBar) > >>> >>> new FooBar // does not log "patched in Element" > >>> >>> ``` > >>> >>> > >>> >>> But when I make a new custom element, constructing it seems to use > >>> >>> the old > >>> >>> Element constructor, as if a non-global reference to the original > >>> >>> constructor is kept inside a module so that modifying the global > >>> >>> wouldn't > >>> >>> have any effect. > >>> >>> > >>> >>> Is there a way to monkey patch a constructor in the middle of a > >>> >>> built-in > >>> >>> prototype chain or to otherwise inject construction logic to base > >>> >>> classes of > >>> >>> existing class hierarchies? > >>> >>> > >>> >>> > >>> >>> /#!/JoePea > >>> >>> > >>> >>> _______________________________________________ > >>> >>> 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 > >> > > > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss >
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