diff --git a/src/services/apis/custom-api.mjs b/src/services/apis/custom-api.mjs
index c2dfafb..df15477 100644
--- a/src/services/apis/custom-api.mjs
+++ b/src/services/apis/custom-api.mjs
@@ -62,12 +62,18 @@ export async function generateAnswersWithCustomApi(port, question, session, apiK
       }
 
       if (data.response) answer = data.response
-      else
-        answer +=
-          data.choices[0]?.delta?.content ||
-          data.choices[0]?.message?.content ||
-          data.choices[0]?.text ||
-          ''
+      else {
+        const delta = data.choices[0]?.delta?.content
+        const content = data.choices[0]?.message?.content
+        const text = data.choices[0]?.text
+        if (delta !== undefined) {
+          answer += delta
+        } else if (content) {
+          answer = content
+        } else if (text) {
+          answer += text
+        }
+      }
       port.postMessage({ answer: answer, done: false, session: null })
     },
     async onStart() {},
diff --git a/src/services/apis/openai-api.mjs b/src/services/apis/openai-api.mjs
index 897da6e..233da93 100644
--- a/src/services/apis/openai-api.mjs
+++ b/src/services/apis/openai-api.mjs
@@ -154,11 +154,16 @@ export async function generateAnswersWithChatgptApiCompat(
         console.debug('json error', error)
         return
       }
-      answer +=
-        data.choices[0]?.delta?.content ||
-        data.choices[0]?.message?.content ||
-        data.choices[0]?.text ||
-        ''
+      const delta = data.choices[0]?.delta?.content
+      const content = data.choices[0]?.message?.content
+      const text = data.choices[0]?.text
+      if (delta !== undefined) {
+        answer += delta
+      } else if (content) {
+        answer = content
+      } else if (text) {
+        answer += text
+      }
       port.postMessage({ answer: answer, done: false, session: null })
     },
     async onStart() {},