refactor: simplify in-page channel event types

Author: posva

packages/devframe/src/in-page-channel/events.test-d.ts

@@ -46,11 +46,3 @@ it('distinguishes void actions from declared events in both directions', () => {
   // @ts-expect-error Functions cannot receive event listeners.
   panel.on('reset', () => {})
 })
-
-it('supports omitted protocol sections without widening their keys', () => {
-  interface FunctionsOnly { functions: { pageScript: { run: () => void } } }
-  interface EventsOnly { events: { panel: { ready: () => void } } }
-  expectTypeOf<Parameters<PanelChannel<FunctionsOnly>['emit']>[0]>().toEqualTypeOf<never>()
-  expectTypeOf<Parameters<PanelChannel<EventsOnly>['call']>[0]>().toEqualTypeOf<never>()
-  expectTypeOf<Parameters<PageScriptChannel<EventsOnly>['on']>[0]>().toEqualTypeOf<never>()
-})

packages/devframe/src/in-page-channel/types.ts

@@ -42,8 +42,6 @@ type PanelFunctions<P extends InPageChannelProtocol> = SideDeclarations<P, 'func
 type SharedStates<P extends InPageChannelProtocol>
   = P['sharedStates'] extends Record<string, object> ? P['sharedStates'] : Record<string, never>
 
-type FunctionNames<T> = { [K in keyof T]: [T[K]] extends [never] ? never : K }[keyof T] & string
-
 type FnArgs<F> = F extends (...args: infer A) => any ? A : never
 type FnReturn<F> = F extends (...args: any[]) => infer R ? Awaited<R> : never
 
@@ -328,7 +326,7 @@ export interface PanelPeer<P extends InPageChannelProtocol> {
   /** Unique id of the panel endpoint (stable across its lifetime, not reloads). */
   readonly id: string
   /** Call one panel's function and await the result. */
-  call: <K extends FunctionNames<PanelFunctions<P>>>(
+  call: <K extends keyof PanelFunctions<P> & string>(
     name: K,
     ...args: FnArgs<PanelFunctions<P>[K]>
   ) => Promise<FnReturn<PanelFunctions<P>[K]>>
@@ -353,17 +351,17 @@ export interface PageScriptChannel<P extends InPageChannelProtocol> {
   readonly panels: readonly PanelPeer<P>[]
   readonly events: Pick<EventEmitter<PageScriptChannelEvents<P>>, 'on' | 'once'>
   /** Fan an event out to every connected panel. */
-  emit: <K extends FunctionNames<PanelProtocolEvents<P>>>(
+  emit: <K extends keyof PanelProtocolEvents<P> & string>(
     name: K,
     ...args: FnArgs<PanelProtocolEvents<P>[K]>
   ) => void
   /** @deprecated Use `emit()` instead. */
-  callEvent: <K extends FunctionNames<PanelProtocolEvents<P>>>(
+  callEvent: <K extends keyof PanelProtocolEvents<P> & string>(
     name: K,
     ...args: FnArgs<PanelProtocolEvents<P>[K]>
   ) => void
   /** Subscribe to an event emitted by a panel. Returns an unsubscribe function. */
-  on: <K extends FunctionNames<PageScriptProtocolEvents<P>>>(
+  on: <K extends keyof PageScriptProtocolEvents<P> & string>(
     name: K,
     listener: (...args: FnArgs<PageScriptProtocolEvents<P>[K]>) => void,
   ) => () => void
@@ -402,25 +400,25 @@ export interface PanelChannel<P extends InPageChannelProtocol> {
    * the call is buffered and sent on connect; it rejects with code
    * `timeout` when `callTimeoutMs` elapses first.
    */
-  call: <K extends FunctionNames<PageScriptFunctions<P>>>(
+  call: <K extends keyof PageScriptFunctions<P> & string>(
     name: K,
     ...args: FnArgs<PageScriptFunctions<P>[K]>
   ) => Promise<FnReturn<PageScriptFunctions<P>[K]>>
   /**
    * Emit an event to the page script. While `connecting` the event is buffered
    * (up to `eventBufferLimit`) and flushed on connect.
    */
-  emit: <K extends FunctionNames<PageScriptProtocolEvents<P>>>(
+  emit: <K extends keyof PageScriptProtocolEvents<P> & string>(
     name: K,
     ...args: FnArgs<PageScriptProtocolEvents<P>[K]>
   ) => void
   /** @deprecated Use `emit()` instead. */
-  callEvent: <K extends FunctionNames<PageScriptProtocolEvents<P>>>(
+  callEvent: <K extends keyof PageScriptProtocolEvents<P> & string>(
     name: K,
     ...args: FnArgs<PageScriptProtocolEvents<P>[K]>
   ) => void
   /** Subscribe to an event emitted by the page script. Returns an unsubscribe function. */
-  on: <K extends FunctionNames<PanelProtocolEvents<P>>>(
+  on: <K extends keyof PanelProtocolEvents<P> & string>(
     name: K,
     listener: (...args: FnArgs<PanelProtocolEvents<P>[K]>) => void,
   ) => () => void

tests/__snapshots__/tsnapi/devframe/in-page-channel.snapshot.d.ts

@@ -4,7 +4,7 @@
 // #region Interfaces
 export interface ConnectPanelChannelOptions<Protocol extends InPageChannelProtocol = InPageChannelProtocol> extends InPageChannelCommonOptions {
   functions: ConnectPanelChannelOptionsFunctions<Protocol>;
-  events: { [NAME in keyof PanelProtocolEvents<Protocol> & string]: InPageEventOption<PanelProtocolEvents<Protocol>[NAME]>; };
+  events?: { [NAME in keyof PanelProtocolEvents<Protocol> & string]?: InPageEventOption<PanelProtocolEvents<Protocol>[NAME]>; };
   window?: Window | false;
   targets?: Window[];
   transport?: MessagePort;
@@ -14,7 +14,7 @@ export interface ConnectPanelChannelOptions<Protocol extends InPageChannelProtoc
 }
 export interface CreatePageScriptChannelOptions<Protocol extends InPageChannelProtocol = InPageChannelProtocol> extends InPageChannelCommonOptions {
   functions: CreatePageScriptChannelOptionsFunctions<Protocol>;
-  events: { [NAME in keyof PageScriptProtocolEvents<Protocol> & string]: InPageEventOption<PageScriptProtocolEvents<Protocol>[NAME]>; };
+  events?: { [NAME in keyof PageScriptProtocolEvents<Protocol> & string]?: InPageEventOption<PageScriptProtocolEvents<Protocol>[NAME]>; };
   window?: Window | false;
 }
 export interface InPageChannelProtocol {
@@ -33,9 +33,9 @@ export interface PageScriptChannel<P extends InPageChannelProtocol> {
   readonly instanceId: string;
   readonly panels: readonly PanelPeer<P>[];
   readonly events: Pick<EventEmitter<PageScriptChannelEvents<P>>, 'on' | 'once'>;
-  emit: <K extends FunctionNames<PanelProtocolEvents<P>>>(_: K, ..._: FnArgs<PanelProtocolEvents<P>[K]>) => void;
-  callEvent: <K extends FunctionNames<PanelProtocolEvents<P>>>(_: K, ..._: FnArgs<PanelProtocolEvents<P>[K]>) => void;
-  on: <K extends FunctionNames<PageScriptProtocolEvents<P>>>(_: K, _: (..._: FnArgs<PageScriptProtocolEvents<P>[K]>) => void) => () => void;
+  emit: <K extends keyof PanelProtocolEvents<P> & string>(_: K, ..._: FnArgs<PanelProtocolEvents<P>[K]>) => void;
+  callEvent: <K extends keyof PanelProtocolEvents<P> & string>(_: K, ..._: FnArgs<PanelProtocolEvents<P>[K]>) => void;
+  on: <K extends keyof PageScriptProtocolEvents<P> & string>(_: K, _: (..._: FnArgs<PageScriptProtocolEvents<P>[K]>) => void) => () => void;
   readonly sharedState: InPageSharedStateHost<P>;
   addPanelPort: (_: MessagePort) => PanelPeer<P>;
   close: () => void;
@@ -48,16 +48,16 @@ export interface PanelChannel<P extends InPageChannelProtocol> {
   } | undefined;
   readonly events: Pick<EventEmitter<PanelChannelEvents>, 'on' | 'once'>;
   whenConnected: (_?: number) => Promise<void>;
-  call: <K extends FunctionNames<PageScriptFunctions<P>>>(_: K, ..._: FnArgs<PageScriptFunctions<P>[K]>) => Promise<FnReturn<PageScriptFunctions<P>[K]>>;
-  emit: <K extends FunctionNames<PageScriptProtocolEvents<P>>>(_: K, ..._: FnArgs<PageScriptProtocolEvents<P>[K]>) => void;
-  callEvent: <K extends FunctionNames<PageScriptProtocolEvents<P>>>(_: K, ..._: FnArgs<PageScriptProtocolEvents<P>[K]>) => void;
-  on: <K extends FunctionNames<PanelProtocolEvents<P>>>(_: K, _: (..._: FnArgs<PanelProtocolEvents<P>[K]>) => void) => () => void;
+  call: <K extends keyof PageScriptFunctions<P> & string>(_: K, ..._: FnArgs<PageScriptFunctions<P>[K]>) => Promise<FnReturn<PageScriptFunctions<P>[K]>>;
+  emit: <K extends keyof PageScriptProtocolEvents<P> & string>(_: K, ..._: FnArgs<PageScriptProtocolEvents<P>[K]>) => void;
+  callEvent: <K extends keyof PageScriptProtocolEvents<P> & string>(_: K, ..._: FnArgs<PageScriptProtocolEvents<P>[K]>) => void;
+  on: <K extends keyof PanelProtocolEvents<P> & string>(_: K, _: (..._: FnArgs<PanelProtocolEvents<P>[K]>) => void) => () => void;
   readonly sharedState: InPageSharedStateHost<P>;
   close: () => void;
 }
 export interface PanelPeer<P extends InPageChannelProtocol> {
   readonly id: string;
-  call: <K extends FunctionNames<PanelFunctions<P>>>(_: K, ..._: FnArgs<PanelFunctions<P>[K]>) => Promise<FnReturn<PanelFunctions<P>[K]>>;
+  call: <K extends keyof PanelFunctions<P> & string>(_: K, ..._: FnArgs<PanelFunctions<P>[K]>) => Promise<FnReturn<PanelFunctions<P>[K]>>;
   close: () => void;
 }
 // #endregion
@@ -94,7 +94,6 @@ type ConnectPanelChannelOptionsFunctions<P extends InPageChannelProtocol> = { [N
 type CreatePageScriptChannelOptionsFunctions<P extends InPageChannelProtocol> = { [NAME in keyof PageScriptFunctions<P> & string]: InPageFunctionOption<PageScriptFunctions<P>[NAME]>; };
 type FnArgs<F> = F extends ((...args: infer A) => any) ? A : never;
 type FnReturn<F> = F extends ((...args: any[]) => infer R) ? Awaited<R> : never;
-type FunctionNames<T> = { [K in keyof T]: [T[K]] extends [never] ? never : K; }[keyof T] & string;
 interface InPageChannelCommonOptions {
   name: string;
   allowedOrigins?: string[];