domenic at domenicdenicola.com (2013-12-10T02:50:12.755Z)
If you have an inner function that calls `super`, Traceur keeps track
of the outer "this" and makes sure to call it with that. TypeScript
does not do this. Is this correct?
```js
class Bar extends Foo {
nestedFunction() {
function run() {
return super.getX();
}
return run();
}
}
```
This code compiles to:
```js
nestedFunction: function() {
var $__0 = this;
function run() {
return $__superCall($__0, $__proto, "getX", []);
}
return run();
}
```
where `$__superCall` basically just does `$__proto["getX"].apply($__0, [])`. But note that it saved the outer `this` in `$__0` and called it with that.
If you have an inner function that calls `super`, Traceur keeps track of the outer "this" and makes sure to call it with that. TypeScript does not do this. Is this correct? ``` class Bar extends Foo { nestedFunction() { function run() { return super.getX(); } return run(); } } ``` This code compiles to: ``` nestedFunction: function() { var $__0 = this; function run() { return $__superCall($__0, $__proto, "getX", []); } return run(); } ``` where `$__superCall` basically just does $__proto["getX"].apply($__0, []). But note that it saved the outer `this` in $__0 and called it with that. On Mon, Dec 9, 2013 at 4:10 PM, Erik Arvidsson <erik.arvidsson at gmail.com> wrote: > TS is known to get this wrong in the name of simplicity. > > Traceur gets it right inside class bodies. We do not support toMethod (not > even sure if this is doable). > > https://github.com/google/traceur-compiler/blob/master/test/feature/Classes/SuperChangeProto.js > http://goo.gl/0kV4ts > > > > > On Mon, Dec 9, 2013 at 12:46 PM, Juan Ignacio Dopazo <jdopazo at yahoo-inc.com> > wrote: >> >> On Mon, Dec 9, 2013 at 2:36 PM, Till Schneidereit >> <till at tillschneidereit.net> wrote: >>> >>> You could also check the output of Traceur and TypeScript. I don't know >>> how close either of them are to implementing the exact semantics of ES6 >>> classes, but I'm sure it'll be helpful in any case. >>> >> >> Yup. See >> http://www.typescriptlang.org/Playground/#src=class%20Person%20%7B%0A%09private%20name%3A%20string%3B%0A%09%0A%09constructor(name)%20%7B%0A%09%09this.name%20%3D%20name%3B%0A%09%7D%0A%09%0A%09say(message%3A%20string)%20%7B%0A%09%09return%20this.name%20%2B%20'%20says%3A%20'%20%2B%20message%3B%0A%09%7D%0A%7D%0A%0Aclass%20Pirate%20extends%20Person%20%7B%0A%09constructor(name)%20%7B%0A%09%09super('Captn%5C'%20'%20%2B%20name)%3B%0A%09%7D%0A%09%0A%09say(message)%20%7B%0A%09%09return%20super.say(message%20%2B%20'%20Arrr!')%3B%0A%09%7D%0A%7D >> >> - Juan >> >> >> On Monday, December 9, 2013 2:37 PM, Till Schneidereit >> <till at tillschneidereit.net> wrote: >> You could also check the output of Traceur and TypeScript. I don't know >> how close either of them are to implementing the exact semantics of ES6 >> classes, but I'm sure it'll be helpful in any case. >> >> >> On Mon, Dec 9, 2013 at 6:28 PM, James Long <longster at gmail.com> wrote: >> >> I read Allen's email wrong, thought it implied `this` was lexically >> scoped (which I know is not true. very little sleep at an airport...). >> >> I'll keep digging through the spec, but if someone has a quick example >> what ES5 code I could compile to for roughly the same semantics, that >> would be helpful. From what I understand, you're saying that `super` >> is lexically scoped to the `class` that is defined so I can statically >> compile it out to something like `Foo.prototype.method` if `Foo` is >> the parent class. Anyway, no need to trail on about this, I should >> just RTFS. >> >> - James >> >> On Mon, Dec 9, 2013 at 11:23 AM, Brendan Eich <brendan at mozilla.com> wrote: >> > OnMon, Dec 9, 2013 at 10:22 AM, Allen Wirfs-Brock >> > >> > <allen at wirfs-brock.com> wrote: >> > >> >> > super is lexically scoped >> > >> > >> > This is true. >> > >> > >> > >> > James Long wrote: >> >> >> >> So essentially super is an alias for `Object.getPrototypeOf(this)` ? >> > >> > >> > But |this| is not lexically scoped, so your question's answer must be >> > "no". >> > >> > /be >> _______________________________________________ >> es-discuss mailing list >> es-discuss at mozilla.org >> https://mail.mozilla.org/listinfo/es-discuss >> >> >> >> _______________________________________________ >> es-discuss mailing list >> es-discuss at mozilla.org >> https://mail.mozilla.org/listinfo/es-discuss >> >> >> >> _______________________________________________ >> es-discuss mailing list >> es-discuss at mozilla.org >> https://mail.mozilla.org/listinfo/es-discuss >> > > > > -- > erik