- From: Jan-Ivar Bruaroey via GitHub <sysbot+gh@w3.org>
- Date: Fri, 30 Sep 2022 17:47:15 +0000
- To: public-webrtc-logs@w3.org
> ... but that's how JavaScript does this.
Default function arguments in JS [seem to work that way, while `??` works another](https://jsfiddle.net/jib1/zoxepamv/), treating `null` and `undefined` the same. But those aren't examples of throwing or rejecting. Where does JS throw or reject on `null`?
If we reject on `null`, then the subset of web developers who operate in larger code bases that use `null` liberally might end up writing defensive code now in order to separate concerns:
```js
async function foo(controller) {
await navigator.mediaDevices.getDisplayMedia({controller: controller ?? undefined});
}
```
This seem sub-optimal. While a controller of `false` or `0` is a type mismatch, `null` isn't in JS (`typeof new CaptureController()` and `typeof null` are both `"object"`).
What's the specific advantage of treating `controller: null` as an error here instead of "no controller"?
Also, when is `null` to be used?
> https://w3ctag.github.io/design-principles/#optional-parameters
This concerns method arguments. Does this mean we're also moving toward:
```js
platformObj.foo("hi", undefined, 3); // accepted
platformObj.foo("hi", null, 3); // TypeError ?
```
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Received on Friday, 30 September 2022 17:47:17 UTC