Need help designing generic function

[sonic prawn]

Hi,

so I have a function like this

function makeListener(event, fn) {}

then I call it like ```js
makeListener("OpenContainer", (event) => {

})

and I have a .d.ts that has a `declare namespace Events {`
that has a `interface OpenContainer extends BaseEvent {`

So, I'd like to make event's type OpenContainer, how would I go about doing that?

I guess I'd also like the event param in makeListener to be typechecked so it has to be one of the interfaces in Events

[quaint ridge]

you need to create a type mapping the event names to event types, then use it to define the signature of makeListener:

[fathom hawk]

mkantor#7432

Playground Link

Preview:```ts
namespace Events {
export interface OpenContainer {
isOpenContainerEvent: true
}
export interface SomeOtherEvent {
isSomeOtherEvent: true
}
}

type EventsByName = {
OpenContainer: Events.OpenContainer
SomeOtherEvent: Events.SomeOtherEvent
...```

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