feat: strongly type event emitter methods #1381
Conversation
Adds strong types to the event emitter interface such that `on` and
similar methods can infer parameters.
For example:
```ts
// these are strongly typed and will give hints in editors etc
watcher.on('ready', () => {});
watcher.on('error', (err) => {});
// this will fail
watcher.on('nonsense', () => {});
```
Fixes #1372
| @@ -58,7 +59,8 @@ export type FSWInstanceOptions = BasicOpts & { | |||
| }; | |||
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| export type ThrottleType = 'readdir' | 'watch' | 'add' | 'remove' | 'change'; | |||
| export type EmitArgs = [EventName, Path | Error, any?, any?, any?]; | |||
| export type EmitArgs = [Path | Error, Stats?]; | |||
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Is that OK for backwards compat?
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Sorry I forgot to reply to this. We do export it so it's technically a breaking change to the types. But as far as I'm aware, it's not part of our "public API".
I couldn't find any usages of it in the wild. So I think it's really just an internal type exported for completeness
| @@ -567,8 +580,8 @@ export class FSWatcher extends EventEmitter { | |||
| } | |||
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| emitWithAll(event: EventName, args: EmitArgs) { | |||
| this.emit(...args); | |||
| if (event !== EV.ERROR) this.emit(EV.ALL, ...args); | |||
| this.emit(event, ...args); | |||
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args used to contain the event name too and we basically didn't make use of event even though we passed it
I simplified so we use the event name and the args separately
We only had them combined for storing in the pending unlinks map. Everywhere else, we already had the name separately or didn't need it
i.e args[0] === event in the existing code
Adds strong types to the event emitter interface such that
onand similar methods can infer parameters.For example:
Fixes #1372
cc @paulmillr