Revert ‘no argument’ conditional type from #3301

solana-labs · Oct 4, 2024 · b4320f5 · b4320f5
1 parent d32e6d6
commit b4320f5
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Showing 2 changed files with 22 additions and 10 deletions.
diff --git a/packages/subscribable/src/__typetests__/data-publisher-typetest.ts b/packages/subscribable/src/__typetests__/data-publisher-typetest.ts
@@ -1,7 +1,7 @@
 /* eslint-disable @typescript-eslint/ban-ts-comment */
 
 import { DataPublisher, getDataPublisherFromEventEmitter } from '../data-publisher';
-import { TypedEventEmitter } from '../event-emitter';
+import { TypedEventEmitter, TypedEventTarget } from '../event-emitter';
 
 type ChannelMap = {
     fall: null;
@@ -12,7 +12,7 @@ const publisher = null as unknown as DataPublisher<ChannelMap>;
 
 // [DESCRIBE] getDataPublisherFromEventEmitter
 {
-    // It materializes listener signatures based on the events of the emitter
+    // It materializes listener signatures based on the events of an event emitter
     {
         const eventEmitter = null as unknown as TypedEventEmitter<{
             baz: Event;
@@ -23,6 +23,22 @@ const publisher = null as unknown as DataPublisher<ChannelMap>;
             data satisfies 'bar';
         });
         publisher.on('baz', (...args) => {
+            // @ts-ignore FIXME: The actual implementation supplies no arguments, not `null`
+            args satisfies [];
+        });
+    }
+    // It materializes listener signatures based on the events of an event target
+    {
+        const eventTarget = null as unknown as TypedEventTarget<{
+            baz: Event;
+            foo: CustomEvent<'bar'>;
+        }>;
+        const publisher = getDataPublisherFromEventEmitter(eventTarget);
+        publisher.on('foo', data => {
+            data satisfies 'bar';
+        });
+        publisher.on('baz', (...args) => {
+            // @ts-ignore FIXME: The actual implementation supplies no arguments, not `null`
             args satisfies [];
         });
     }

diff --git a/packages/subscribable/src/data-publisher.ts b/packages/subscribable/src/data-publisher.ts
@@ -1,23 +1,19 @@
-import { TypedEventEmitter } from './event-emitter';
+import { TypedEventEmitter, TypedEventTarget } from './event-emitter';
 
 type UnsubscribeFn = () => void;
 
 export interface DataPublisher<TDataByChannelName extends Record<string, unknown> = Record<string, unknown>> {
     on<const TChannelName extends keyof TDataByChannelName>(
         channelName: TChannelName,
-        subscriber: (
-            ...data: TDataByChannelName[TChannelName] extends never ? [] : [data: TDataByChannelName[TChannelName]]
-        ) => void,
+        subscriber: (data: TDataByChannelName[TChannelName]) => void,
         options?: { signal: AbortSignal },
     ): UnsubscribeFn;
 }
 
 export function getDataPublisherFromEventEmitter<TEventMap extends Record<string, Event>>(
-    eventEmitter: TypedEventEmitter<TEventMap>,
+    eventEmitter: TypedEventEmitter<TEventMap> | TypedEventTarget<TEventMap>,
 ): DataPublisher<{
-    [TEventType in keyof TEventMap]: TEventMap[TEventType] extends CustomEvent
-        ? TEventMap[TEventType]['detail']
-        : never;
+    [TEventType in keyof TEventMap]: TEventMap[TEventType] extends CustomEvent ? TEventMap[TEventType]['detail'] : null;
 }> {
     return {
         on(channelName, subscriber, options) {