On Thu, Apr 19, 2018 at 11:49 PM, Isiah Meadows <[email protected]>
wrote:
>
> Here's my proposal:
>
> In constructors, currently, non-objects are replaced with `this`.
> Here's what I think it should be replaced with:
>
> 1. When calling the constructor, if `undefined` is returned and
> `new.target` is not `undefined`, return `this` instead. This is for
> compatibility and ease of implementation.
> 1. When calling the constructor, if anything else is returned, return
> that value in raw form.
I think you'll struggle to demonstrate that this is web-safe; certainly
doing so would be a major undertaking.
One particular habit that would be of concern is people writing:
```js
if (condition) return someFunction();
```
instead of
```js
if (condition) {
someFunction();
return;
}
```
...when they know full well that they don't actually want to return the
result of `someFunction`. Mostly I see that in Node-style callbacks where
the return value is ignored, but it wouldn't surprise me at all if there
was code in the wild that did that in a constructor, happily (and probably
unintentaionally) taking advantage of the fact that the return value will
be ignored.
Horribly contrived example:
```js
class Multiplier {
constructor(a, b) {
if (typeof a === "undefined") {
this.setA(7);
return this.setB(6);
}
this.setA(a);
this.setB(b);
}
setA(value) {
return this.a = value;
}
setB(value) {
return this.b = value;
}
execute() {
return this.a * this.b;
}
}
const m = new Multiplier();
console.log(m.execute());
```
And just generally, changing a behavior that's so well-established without
some kind of mode (and I'm told There Will Be No More Modes) seems like
asking for trouble. Would need to have a massive, unambiguous benefit.
-- T.J. Crowder
_______________________________________________
es-discuss mailing list
[email protected]
https://mail.mozilla.org/listinfo/es-discuss
