Pass through errors that are not HTTP, but include response

src/Error.ts

@@ -6,6 +6,8 @@ export class JSONRPCError extends Error {
   public message: string;
   public code: number;
   public data?: unknown;
+  // For transports that run over Fetch.
+  public response?: Response;
   constructor(message: string, code: number, data?: any) {
     super(message);
     this.message = message;

src/transports/HTTPTransport.ts

@@ -39,8 +39,9 @@ class HTTPTransport extends Transport {
     const notifications = getNotifications(data);
     const batch = getBatchRequests(data);
     const fetcher = this.injectedFetcher || fetch;
+    let result;
     try {
-      const result = await fetcher(this.uri, {
+      result = await fetcher(this.uri, {
         method: "POST",
         headers: this.headers,
         body: JSON.stringify(this.parseData(data)),
@@ -54,7 +55,7 @@ class HTTPTransport extends Transport {
       const body = await result.text();
       const responseErr = this.transportRequestManager.resolveResponse(body);
       if (responseErr) {
-        // requirements are that batch requuests are successfully resolved
+        // requirements are that batch requests are successfully resolved
         // this ensures that individual requests within the batch request are settled
         this.transportRequestManager.settlePendingRequest(batch, responseErr);
         return Promise.reject(responseErr);

src/transports/TransportRequestManager.ts

@@ -124,17 +124,19 @@ export class TransportRequestManager {
   private resolveRes(data: IJSONRPCNotificationResponse | IJSONRPCResponse, emitError: boolean): TransportResponse {
     const { id, error } = data;
 
-    const status = this.pendingRequest[id as string];
-    if (status) {
-      delete this.pendingRequest[id as string];
-      this.processResult(data, status);
-      this.transportEventChannel.emit("response", data as IJSONRPCResponse);
-      return;
-    }
     if (id === undefined && error === undefined) {
       this.transportEventChannel.emit("notification", data as IJSONRPCNotificationResponse);
       return;
     }
+    const status = this.pendingRequest[id as string];
+    if (status) {
+      delete this.pendingRequest[id as string];
+      if (error === undefined) {
+        this.processResult(data, status);
+        this.transportEventChannel.emit("response", data as IJSONRPCResponse);
+        return;
+      }
+    }
     let err;
     if (error) {
       err = convertJSONToRPCError(data);