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Obsolescence of __noSuchMethod__
Posted: Sun Mar 29, 2015 9:52 pm
by barbaz
This is going to break a LOT of our surrogates.
EDIT SeaMonkey 2.37a1 gives this warning in the Error Console when a __noSuchMethod__ is hit:
Code: Select all
Warning: Error: __noSuchMethod__ is deprecated
Also, as of the time of this edit I have not seen or come up with any Proxy-based emulation of __noSuchMethod__ that is limited to function calls - in fact I don't even know if Proxy can tell whether a property is accessed as part of a function call... does that matter?
Re: Obsolescence of __noSuchMethod__
Posted: Fri Apr 24, 2015 1:15 am
by barbaz
So I've played with Proxy (fun stuff!
) and thought about this... and I think that Proxy trapping all property acesses is actually going to make the surrogates more stable than the current __noSuchMethod__.. I recently contributed a surrogate where the page explicitly checked for a property before using it, and unlike __noSuchMethod__, where I had to explicitly specify the property, the use of Proxy would have meant that it makes no difference.
So I think we only need to intercept the get() operation with a shim something like this:
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let canUseProxy = typeof Proxy != 'undefined';
if (canUseProxy) {
someObject = new Proxy(_internal_someObject, {
get: function(target, prop, rcv) {
// Emulate __noSuchMethod__: Give a specified function that does nothing if the property isn't in our object
// NOTE: This assumes all nonexistant properties attempted to be accessed were meant to be functions. Be careful here...
return prop in target ? target[prop] : target['__noSuchMethod__'];
},
});
}
right?
(Obviously we wouldn't want to override __noSuchMethod__ at this point, rather using some other name if we make the switch now. But when __noSuchMethod__ becomes obsolete...)
Re: Obsolescence of __noSuchMethod__
Posted: Wed Jul 22, 2015 6:13 pm
by barbaz
Re: Obsolescence of __noSuchMethod__
Posted: Wed Jul 22, 2015 7:30 pm
by therube
(Since when did "popularity" mean anything in Mozilla decisions
.)
Re: Obsolescence of __noSuchMethod__
Posted: Tue Jul 28, 2015 7:42 pm
by barbaz
Does this change mean this thread can be marked resolved?
Re: Obsolescence of __noSuchMethod__
Posted: Fri Feb 19, 2016 5:59 am
by fluffypuff
noscript-2.9.0.4rc1 (noscriptService.js) still relies on __noSuchMethod__ but, as of ff44, mozilla has removed it
https://developer.mozilla.org/en-US/Firefox/Releases/44
After reading the MDN docs regarding js proxy
https://developer.mozilla.org/en-US/doc ... ects/Proxy and
https://developer.mozilla.org/en-US/doc ... e[quote]if the revoke() function gets called, the proxy becomes unusable: Any trap to a handler will throw a TypeError. Once a proxy is revoked, it will remain revoked and can be garbage collected.[/quote]...I'm left wondering whether proxying will provide ineffectual functionality.
For surrogates, the proxy declaration(s) reside within contentscript, right?
What's to prevent, e.g. anti-adblock script authors, enumerating and revoking any proxies we've created?
Then, after reading this
https://ponyfoo.com/articles/es6-proxies-in-depth
I'm now wondering whether we could (should?) both create AND proactively revoke() to achieve the same end result as provided by __noSuchMethod__
Re: Obsolescence of __noSuchMethod__
Posted: Sat Feb 20, 2016 11:05 am
by Thrawn
I think perhaps you don't understand the workings of the Proxy object. How much JavaScript experience do you have?