init requires a mediaElement, but setSource does not?

[larrywal]

Hi - am trying to use peaks.js to generate waveforms on the fly using WebAudio. I notice that with SetSource I can pass just a mediaURL and webAudio.audioContext. But on init, I must pass a mediaElement that contains the fileURL as its src.  Otherwise the init never seems to return.  Is this expected behavior?

[chrisn]

Peaks.init() should always return. If there's an error, it should call the callback parameter with an Error object. What combination of options are you passing to Peaks.init()?

[larrywal]

Thanks for the quick response! Here's the code I'm using. When I comment out the line audio.current!.src = fileURL then the code after init never seems to run.

[chrisn]

Thanks. Currently, Peaks.init() doesn't accept a mediaUrl option, so - as you've found - you need to set the media element's src attribute before calling Peaks.init().

I'll look into making Peaks.init() more consistent with .setSource().

[larrywal]

Got it - thanks much.

On Thu, Nov 12, 2020 at 9:12 AM Chris Needham [email protected] wrote:

Thanks. Currently, Peaks.init() doesn't accept a mediaUrl option, so - as you've found - you need to set the media element's src attribute before calling Peaks.init().

I'll look into making Peaks.init() more consistent with .setSource().

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[rowild]

Never seen this notation: audio.current!.src = [...]

Trying to find documentation for that, but I fail. Is this correct? What do I have to search for, if I want to learn about this specific NOT notation?

[chrisn]

It's a TypeScript feature: https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-0.html#non-null-assertion-operator

[chrisn]

Calling Peaks.init() with an empty <audio> element (i.e., no src attribute and no <source> elements), the callback is never invoked. See:

https://github.com/bbc/peaks.js/blob/ab1413560e24426aa55c13898b3d006b20ffc746/src/mediaelement-player.js#L75