Event type of midiInput.onmidimessage wrong

[h-a-n-n-e-s]

This

midiInput.onmidimessage = handleMIDIMessage;
with
handleMIDIMessage = (event:MIDIMessageEvent) => {...}

runs perfectly fine in the browser, but the TypeScript compiler throws this error:

Type '(event: MIDIMessageEvent) => void' is not assignable to type '(this: MIDIInput, ev: Event) => any'.
Types of parameters 'event' and 'ev' are incompatible.
Property 'data' is missing in type 'Event' but required in type 'MIDIMessageEvent'.

Shouldn't midiInput.onmidimessage have the type (this: MIDIInput, ev: MIDIMessageEvent) => any instead of (this: MIDIInput, ev: Event) => any ?

According to this
https://developer.mozilla.org/en-US/docs/Web/API/MIDIMessageEvent
it should.

Thanks!

[christiaanwesterbeek]

I encountered this too. In my Chrome browser I can do this and it works.

midiInput.onmidimessage = (msg) => {
    const [status, note, velocity] = msg.data;
    console.log(msg);
}

But still typescript complains that:

Property 'data' does not exist on type 'Event'. ts(2339)

I changed my code to the following and the typescript error is gone.

midiInput.onmidimessage = (msg: MIDIMessageEvent) => {
    const [status, note, velocity] = msg.data;
    console.log(msg);
}

[h-a-n-n-e-s]

@christiaanwesterbeek
Yes, this is exactly what I do too, but Typescript erroneously expects type Event for msg and throws the error.

[fa-sharp]

Just submitted a PR to fix this :)

[h-a-n-n-e-s]

@fa-sharp
Why can I not see your merge in my typescript 5.3.3 installation?
Shouldn't all updates here automatically be included in all typescript releases?

[fa-sharp]

@h-a-n-n-e-s Hmm, good question! I did assume it was automatic but maybe it isn't anymore.

I did a little digging, and I think the last time the DOM types from this library were merged into TypeScript was this PR: microsoft/TypeScript#55798. So we might need to wait until TS 5.4 until the new types are merged? 🤷

[h-a-n-n-e-s]

@fa-sharp Oh, I see. Then lets wait for the next minor release! ☺️ Thanks!

[h-a-n-n-e-s]

@fa-sharp In TS 5.4 it's merged! ☺️ Thanks again for your help!