Allow reading multiple data chunks from single read() chunk.

Author: taeold

packages/functions/src/service.ts

@@ -107,7 +107,7 @@ export class FunctionsService implements _FirebaseService {
     messagingProvider: Provider<MessagingInternalComponentName>,
     appCheckProvider: Provider<AppCheckInternalComponentName>,
     regionOrCustomDomain: string = DEFAULT_REGION,
-    readonly fetchImpl: typeof fetch = fetch,
+    readonly fetchImpl: typeof fetch = (...args) => fetch(...args),
   ) {
     this.contextProvider = new ContextProvider(
       authProvider,
@@ -450,6 +450,7 @@ async function streamAtURL(
   const reader = response.body!.getReader();
   const decoder = new TextDecoder();
 
+  let pendingLines: string[] = [];
   let buffer = '';
   let resultResolver: (value: unknown) => void;
   let resultRejecter: (reason: any) => void;
@@ -470,6 +471,30 @@ async function streamAtURL(
 
   const stream = {
     [Symbol.asyncIterator]() {
+
+      const processLine = (line: string | undefined) => {
+        // ignore all other lines (newline, comments, etc.)
+        if (!line?.startsWith('data: ')) return null;
+
+        try {
+          const jsonData = JSON.parse(line.slice(6));
+          if ('result' in jsonData) {
+            resultResolver(decode(jsonData.result));
+            return { done: true, value: undefined };
+          }
+          if ('message' in jsonData) {
+            return { done: false, value: decode(jsonData.message) };
+          }
+          if ('error' in jsonData) {
+            const error = _errorForResponse(0, jsonData);
+            resultRejecter(error);
+            throw error;
+          }
+          return null; // Unrecognize keys. Skip this line.
+        } catch (error) {
+          // Not json. Skip this line.
+        }
+      };
       return {
         async next() {
           if (options?.signal?.aborted) {
@@ -481,29 +506,30 @@ async function streamAtURL(
             throw error;
           }
 
+          while (pendingLines.length > 0) {
+            const result = processLine(pendingLines.shift());
+            if (result) return result;
+          }
+
           while (true) {
             const { value, done } = await reader.read();
-            if (done) return { done: true, value: undefined };
+
+            if (done) {
+              if (buffer.trim()) {
+                const result = processLine(buffer);
+                if (result) return result;
+              }
+              return { done: true, value: undefined };
+            }
 
             buffer += decoder.decode(value, { stream: true });
             const lines = buffer.split('\n');
             buffer = lines.pop() || '';
+            pendingLines.push(...lines.filter(line => line.trim()));
 
-            for (const line of lines) {
-              if (line.startsWith('data: ')) {
-                const jsonData = JSON.parse(line.slice(6));
-                if ('result' in jsonData) {
-                  resultResolver(decode(jsonData.result));
-                  return { done: true, value: undefined };
-                } else if ('message' in jsonData) {
-                  return { done: false, value: decode(jsonData.message) };
-                } else if ('error' in jsonData) {
-                  const error = _errorForResponse(0, jsonData);
-                  resultRejecter(error)
-                  throw error;
-                }
-              }
-              // ignore all other lines (newline, comments, etc.)
+            if (pendingLines.length > 0) {
+              const result = processLine(pendingLines.shift());
+              if (result) return result;
             }
           }
         }