Make the data property of MessageEvent generic

[cawa-93]

Fix microsoft/TypeScript#19370

[ghost]

All CLA requirements met.

[CKGrafico]

We still have the message "MessageEvent" is not generic when

window.addEventListener('message', (event: MessageEvent<CustomDataType>) => {})

[sapter]

I'm also still getting an error Type 'MessageEvent' is not generic. @CKGrafico have you been able to resolve this or figure out why we're still getting an error? I'm on TS v4.2.2

[CKGrafico]

@sapter nop sorry, there is the worst workaround in the world :'(

 window.addEventListener('message', (event: MessageEvent) => {
      const data: PanelMessage = event.data;

[bb-in-hoodie]

There is no error underline in VSCode, but it keeps yield an error message in terminal when the code gets built.
Type 'MessageEvent' is not generic.
Is there no fix yet?

[saschanaz]

There is no error underline in VSCode, but it keeps yield an error message in terminal when the code gets built.
Type 'MessageEvent' is not generic.
Is there no fix yet?

I think your local TypeScript version is low in that case.

[bb-in-hoodie]

I think your local TypeScript version is low in that case.

since which TS version does support this typing?
I'm on v3.9.6 for now.

[cawa-93]

since which TS version does support this typing?

@bb-in-hoodie >= v4.

You can test it in playground

[bb-in-hoodie]

Thank you 👍 I'll try it