Only ignore empty text parts in the aggregated response.

Author: dlarocque

packages/vertexai/src/requests/stream-reader.test.ts

@@ -17,7 +17,6 @@
 
 import {
   aggregateResponses,
-  deleteEmptyTextParts,
   getResponseStream,
   processStream
 } from './stream-reader';
@@ -34,7 +33,6 @@ import {
   GenerateContentResponse,
   HarmCategory,
   HarmProbability,
-  Part,
   SafetyRating
 } from '../types';
 
@@ -228,6 +226,7 @@ describe('processStream', () => {
     );
     const result = processStream(fakeResponse as Response);
     const aggregatedResponse = await result.response;
+    console.log(aggregatedResponse.candidates?.[0].content.parts);
     expect(aggregatedResponse.text()).to.equal('1');
     expect(aggregatedResponse.candidates?.length).to.equal(1);
     expect(aggregatedResponse.candidates?.[0].content.parts.length).to.equal(1);
@@ -423,104 +422,3 @@ describe('aggregateResponses', () => {
     });
   });
 });
-
-describe('deleteEmptyTextParts', () => {
-  it('removes empty text parts from a single candidate', () => {
-    const parts: Part[] = [
-      {
-        text: ''
-      },
-      {
-        text: 'foo'
-      }
-    ];
-    const generateContentResponse: GenerateContentResponse = {
-      candidates: [
-        {
-          index: 0,
-          content: {
-            role: 'model',
-            parts
-          }
-        }
-      ]
-    };
-
-    deleteEmptyTextParts(generateContentResponse);
-    expect(generateContentResponse.candidates?.[0].content.parts).to.deep.equal(
-      [
-        {
-          text: 'foo'
-        }
-      ]
-    );
-  });
-  it('removes empty text parts from all candidates', () => {
-    const parts: Part[] = [
-      {
-        text: ''
-      },
-      {
-        text: 'foo'
-      }
-    ];
-    const generateContentResponse: GenerateContentResponse = {
-      candidates: [
-        {
-          index: 0,
-          content: {
-            role: 'model',
-            parts
-          }
-        },
-        {
-          index: 1,
-          content: {
-            role: 'model',
-            parts
-          }
-        }
-      ]
-    };
-
-    deleteEmptyTextParts(generateContentResponse);
-    expect(generateContentResponse.candidates?.[0].content.parts).to.deep.equal(
-      [
-        {
-          text: 'foo'
-        }
-      ]
-    );
-    expect(generateContentResponse.candidates?.[1].content.parts).to.deep.equal(
-      [
-        {
-          text: 'foo'
-        }
-      ]
-    );
-  });
-  it('does not remove candidate even if all parts are removed', () => {
-    const parts: Part[] = [
-      {
-        text: ''
-      }
-    ];
-    const generateContentResponse: GenerateContentResponse = {
-      candidates: [
-        {
-          index: 0,
-          content: {
-            role: 'model',
-            parts
-          }
-        }
-      ]
-    };
-
-    deleteEmptyTextParts(generateContentResponse);
-    expect(generateContentResponse.candidates?.length).to.equal(1);
-    expect(generateContentResponse.candidates?.[0].content.parts).to.deep.equal(
-      []
-    );
-  });
-});

packages/vertexai/src/requests/stream-reader.ts

@@ -63,7 +63,6 @@ async function getResponsePromise(
       return enhancedResponse;
     }
 
-    deleteEmptyTextParts(value);
     allResponses.push(value);
   }
 }
@@ -78,7 +77,6 @@ async function* generateResponseSequence(
       break;
     }
 
-    deleteEmptyTextParts(value);
     const enhancedResponse = createEnhancedContentResponse(value);
     yield enhancedResponse;
   }
@@ -187,7 +185,13 @@ export function aggregateResponses(
           }
           const newPart: Partial<Part> = {};
           for (const part of candidate.content.parts) {
-            if (part.text) {
+            if (part.text !== undefined) {
+              // The backend can send empty text parts. If these are sent back
+              // (e.g. in chat history), the backend will respond with an error.
+              // To prevent this, ignore empty text parts.
+              if (part.text === '') {
+                continue;
+              }
               newPart.text = part.text;
             }
             if (part.functionCall) {
@@ -206,21 +210,3 @@ export function aggregateResponses(
   }
   return aggregatedResponse;
 }
-
-/**
- * The backend can send empty text parts, but if they are sent back (e.g. in a chat history) there
- * will be an error. To prevent this, filter out the empty text part from responses.
- *
- * See: https://github.com/firebase/firebase-js-sdk/issues/8714
- */
-export function deleteEmptyTextParts(response: GenerateContentResponse): void {
-  if (response.candidates) {
-    response.candidates.forEach(candidate => {
-      if (candidate.content && candidate.content.parts) {
-        candidate.content.parts = candidate.content.parts.filter(
-          part => part.text !== ''
-        );
-      }
-    });
-  }
-}