Improve recognizer event listener handling

lib/package.json

@@ -33,7 +33,7 @@
     "rollup-plugin-web-worker-loader": "^1.6.0",
     "ts-loader": "^8.0.17",
     "tslib": "^2.1.0",
-    "typescript": "^4.1.5",
+    "typescript": "^4.6.2",
     "worker-loader": "^3.0.8"
   }
 }

lib/src/interfaces.ts

@@ -94,11 +94,13 @@ export interface ServerMessageLoadResult {
 
 export interface ServerMessageError {
   event: "error";
+  recognizerId?: string;
   error: string;
 }
 
 export interface ServerMessageResult {
   event: "result";
+  recognizerId: string;
   result: {
     result: Array<{
       conf: number;
@@ -111,6 +113,7 @@ export interface ServerMessageResult {
 }
 export interface ServerMessagePartialResult {
   event: "partialresult";
+  recognizerId: string;
   result: {
     partial: string;
   };
@@ -127,19 +130,20 @@ export namespace ModelMessage {
 }
 export type RecognizerMessage =
   | ServerMessagePartialResult
-  | ServerMessageResult;
+  | ServerMessageResult
+  | ServerMessageError;
 
 export type RecognizerEvent = RecognizerMessage["event"];
 
 export type ServerMessage = ModelMessage | RecognizerMessage;
 
 export namespace ServerMessage {
-  export function isRecognizerMessage(message: ServerMessage): boolean {
-    return ["result", "partialresult"].includes(message.event);
+  export function isRecognizerMessage(message: ServerMessage): message is RecognizerMessage {
+    return ["result", "partialresult"].includes(message.event) || Reflect.has(message, 'recognizerId');
   }
 
   export function isResult(message: any): message is ServerMessageResult {
-    return message?.result?.text != null;
+    return message?.result?.text != null || message?.result?.result != null;
   }
 
   export function isPartialResult(

lib/src/model.ts

@@ -22,6 +22,7 @@ export class Model extends EventTarget {
   private _ready: boolean = false;
   private messagePort: MessagePort;
   private logger: Logger = new Logger();
+  private recognizers = new Map<string, KaldiRecognizer>();
 
   constructor(private modelUrl: string, logLevel: number = 0) {
     super();
@@ -51,7 +52,7 @@ export class Model extends EventTarget {
 
   private postMessage<T = ClientMessage>(
     message: T,
-    options?: PostMessageOptions
+    options?: StructuredSerializeOptions
   ) {
     this.worker.postMessage(message, options);
   }
@@ -63,7 +64,16 @@ export class Model extends EventTarget {
         this._ready = message.result;
       }
 
-      this.dispatchEvent(new CustomEvent(message.event, { detail: message }));
+      const event = new CustomEvent(message.event, { detail: message });
+      if (ServerMessage.isRecognizerMessage(message) && message.recognizerId) {
+        const recognizer = this.recognizers.get(message.recognizerId);
+        if (recognizer) {
+          recognizer.dispatchEvent(event);
+          return;
+        }
+      }
+
+      this.dispatchEvent(event);
     }
   }
 
@@ -115,6 +125,14 @@ export class Model extends EventTarget {
     );
   }
 
+  public registerRecognizer(recognizer: KaldiRecognizer) {
+    this.recognizers.set(recognizer.id, recognizer);
+  }
+
+  public unregisterRecognizer(recognizerId: string) {
+    this.recognizers.delete(recognizerId);
+  }
+
   /**
    * KaldiRecognizer anonymous class
    */
@@ -129,6 +147,9 @@ export class Model extends EventTarget {
             "Cannot create KaldiRecognizer. Model is either not ready or has been terminated"
           );
         }
+
+        model.registerRecognizer(this);
+
         model.postMessage<ClientMessageCreateRecognizer>({
           action: "create",
           recognizerId: this.id,
@@ -141,10 +162,8 @@ export class Model extends EventTarget {
         event: RecognizerEvent,
         listener: (message: RecognizerMessage) => void
       ) {
-        model.addEventListener(event, (event: any) => {
-          if (event.detail && ServerMessage.isRecognizerMessage(event.detail)) {
-            listener(event.detail);
-          }
+        this.addEventListener(event, (event: any) => {
+          listener(event?.detail);
         });
       }
 
@@ -193,6 +212,8 @@ export class Model extends EventTarget {
       }
 
       public remove(): void {
+        model.unregisterRecognizer(this.id);
+
         model.postMessage<ClientMessageRemoveRecognizer>({
           action: "remove",
           recognizerId: this.id,

lib/src/worker.ts

@@ -43,6 +43,7 @@ export class RecognizerWorker {
 
       if (!modelUrl) {
         ctx.postMessage({
+          event: "error",
           error: "Missing modelUrl parameter",
         });
       }
@@ -53,7 +54,7 @@ export class RecognizerWorker {
         })
         .catch((error) => {
           this.logger.error(error);
-          ctx.postMessage({ error: error.message });
+          ctx.postMessage({ event: "error", error: error.message });
         });
 
       return;
@@ -69,7 +70,7 @@ export class RecognizerWorker {
         .then((result) => {
           ctx.postMessage(result);
         })
-        .catch((error) => ctx.postMessage({ event: "error", error }));
+        .catch((error) => ctx.postMessage({ event: "error", recognizerId: message.recognizerId, error: error.message }));
       return;
     }
 
@@ -78,7 +79,7 @@ export class RecognizerWorker {
         .then((result) => {
           ctx.postMessage(result);
         })
-        .catch((error) => ctx.postMessage({ event: "error", error }));
+        .catch((error) => ctx.postMessage({ event: "error", recognizerId: message.recognizerId, error: error.message }));
       return;
     }
 
@@ -87,7 +88,7 @@ export class RecognizerWorker {
         .then((result) => {
           ctx.postMessage(result);
         })
-        .catch((error) => ctx.postMessage({ event: "error", error }));
+        .catch((error) => ctx.postMessage({ event: "error", recognizerId: message.recognizerId, error: error.message }));
       return;
     }
 
@@ -96,7 +97,7 @@ export class RecognizerWorker {
       return;
     }
 
-    ctx.postMessage({ error: `Unknown message ${JSON.stringify(message)}` });
+    ctx.postMessage({ event: "error", error: `Unknown message ${JSON.stringify(message)}` });
   }
 
   private async load(modelUrl: string): Promise<boolean> {
@@ -110,6 +111,7 @@ export class RecognizerWorker {
         })
         .catch((e) => {
           this.logger.error(e);
+          reject(e);
         })
     )
       .then(() => {
@@ -196,9 +198,7 @@ export class RecognizerWorker {
     } catch (error) {
       const errorMsg = `Recognizer (id: ${recognizerId}): Could not be created due to: ${error}\n${(error as Error)?.stack}`;
       this.logger.error(errorMsg);
-      return {
-        error: errorMsg,
-      };
+      throw new Error(errorMsg);
     }
   }
 
@@ -242,10 +242,8 @@ export class RecognizerWorker {
     );
 
     if (!this.recognizers.has(recognizerId)) {
-      this.logger.warn(`Recognizer not ready, ignoring`);
-      return {
-        error: `Recognizer (id: ${recognizerId}): Not ready`,
-      };
+      this.logger.error(`Recognizer (id: ${recognizerId}) not ready, ignoring`);
+      throw new Error(`Recognizer (id: ${recognizerId}): Not ready`);
     }
 
     let recognizer = this.recognizers.get(recognizerId)!;
@@ -275,9 +273,7 @@ export class RecognizerWorker {
     if (recognizer.buffAddr == null) {
       const error = `Recognizer (id: ${recognizer.id}): Could not allocate buffer`;
       this.logger.error(error);
-      return {
-        error
-      };
+      throw new Error(error);
     }
 
     this.Vosk.HEAPF32.set(data, recognizer.buffAddr / data.BYTES_PER_ELEMENT);
@@ -327,7 +323,11 @@ export class RecognizerWorker {
 
   private async terminate() {
     for (const recognizer of this.recognizers.values()) {
-      await this.removeRecognizer(recognizer.id);
+      try {
+        await this.removeRecognizer(recognizer.id);
+      } catch (error) {
+        this.logger.warn(`Recognizer (id: ${recognizer.id}) could not be removed. Ignoring as we are terminating.`)
+      } 
     }
     this.model.delete();
     close();