Bug 188834 – AudioNode.connect does not return destination node

• Component: Web Audio
• Status: RESOLVED FIXED

[jakubfiala]

According to the Web Audio spec https://webaudio.github.io/web-audio-api/#dom-audionode-connect

AudioNode.connect "returns destination AudioNode object".

This does not seem to be the case in both iOS Safari 11 and desktop Safari 11, where AudioNode.connect returns `undefined`. It's problematic for code which uses chaining of .connect methods.

Steps to reproduce:

> const ac = new webkitAudioContext()
< undefined
> g1 = ac.createGain()
< GainNode {gain: AudioParam, context: webkitAudioContext, numberOfInputs: 1, numberOfOutputs: 1, channelCount: 2, …}
> g2 = ac.createGain()
< GainNode {gain: AudioParam, context: webkitAudioContext, numberOfInputs: 1, numberOfOutputs: 1, channelCount: 2, …}
> g3 = ac.createGain()
< GainNode {gain: AudioParam, context: webkitAudioContext, numberOfInputs: 1, numberOfOutputs: 1, channelCount: 2, …}
> g1.connect(g2).connect(g3)
< TypeError: undefined is not an object (evaluating 'g1.connect(g2).connect')

[Radar WebKit Bug Importer]

<rdar://problem/43609703>

[Walker Henderson]

I started work on a patch for this.

[Walker Henderson]

Created attachment 351198 [details]
Patch

[Eric Carlson]

Comment on attachment 351198 [details]
Patch

Thank you!

[WebKit Commit Bot]

Comment on attachment 351198 [details]
Patch

Clearing flags on attachment: 351198

Committed r236648: <https://trac.webkit.org/changeset/236648>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.

[Darin Adler]

Comment on attachment 351198 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=351198&action=review

> Source/WebCore/Modules/webaudio/AudioNode.idl:37
> -    [MayThrowException] void connect(AudioNode destination, optional unsigned long output = 0, optional unsigned long input = 0);
> +    [MayThrowException] AudioNode connect(AudioNode destination, optional unsigned long output = 0, optional unsigned long input = 0);

I believe there is a slightly more efficient way to do this by using the [ReturnValue] attribute on the destination object, so the JavaScript binding will reuse the passed-in wrapper rather than having to look it up.

[Walker Henderson]

Comment on attachment 351198 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=351198&action=review

>> Source/WebCore/Modules/webaudio/AudioNode.idl:37
>> +    [MayThrowException] AudioNode connect(AudioNode destination, optional unsigned long output = 0, optional unsigned long input = 0);
> 
> I believe there is a slightly more efficient way to do this by using the [ReturnValue] attribute on the destination object, so the JavaScript binding will reuse the passed-in wrapper rather than having to look it up.

Gotcha, should I put together a new patch for that? If so, should the patch be attached to a new bug?

[Eric Carlson]

(In reply to Walker Henderson from comment #8)
> Comment on attachment 351198 [details]
> Patch
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=351198&action=review
> 
> >> Source/WebCore/Modules/webaudio/AudioNode.idl:37
> >> +    [MayThrowException] AudioNode connect(AudioNode destination, optional unsigned long output = 0, optional unsigned long input = 0);
> > 
> > I believe there is a slightly more efficient way to do this by using the [ReturnValue] attribute on the destination object, so the JavaScript binding will reuse the passed-in wrapper rather than having to look it up.
> 
> Gotcha, should I put together a new patch for that? If so, should the patch
> be attached to a new bug?

Why don't you file a new bug and reference this.

[Darin Adler]

I threw together a patch for this already. Filed bug 190231.