修改科目编码

src/views/targetImprove/practice/index.vue

@@ -55,24 +55,24 @@ export default {
     }
   },
   computed:{
-    ...mapState('target', ['subjectCode'])
+    ...mapState('target', ['subjectCode', 'levelCode'])
   },
   inject: ['openAiRobot'],//注入Ai机器人组件调用方法
   watch:{
-    // 监听顶部的subjectCode变化
-    subjectCode(newVal, oldVal){
-      console.log('科目编码改变了', newVal, oldVal)
-      // ========= 业务逻辑写这里 =========
-      // 例如：切换科目，重置步骤、重新请求知识点图谱数据
-      if (newVal) {
-        this.FetchWaitExerciseNum();
-      }
+    subjectCode(newVal){
+      if (newVal) this.scheduleFetchWaitExerciseNum();
+    },
+    levelCode(newVal){
+      if (newVal) this.scheduleFetchWaitExerciseNum();
     }
   },
 
   mounted() 
   {
-    this.FetchWaitExerciseNum();
+    this.scheduleFetchWaitExerciseNum();
+  },
+  beforeDestroy() {
+    clearTimeout(this._waitNumTimer);
   },
   methods: { 
 
@@ -94,11 +94,24 @@ export default {
       }
     },
 
+    /**
+     * 科目、学段同一时刻先后就绪时，合并成一次请求
+     */
+    scheduleFetchWaitExerciseNum()
+    {
+      clearTimeout(this._waitNumTimer);
+      this._waitNumTimer = setTimeout(() => {
+        this.FetchWaitExerciseNum();
+      }, 0);
+    },
+
     // 获取知识点练习作答待练习数量
     FetchWaitExerciseNum()
     {
-      const levelCode = localStorage.getItem('student_level_code') || '';
+      const levelCode = this.levelCode || localStorage.getItem('student_level_code') || '';
       const subjectCode = this.subjectCode || '';
+      // 登录后头部数据未回来前不请求，避免空参导致 500
+      if (!levelCode || !subjectCode) return;
       this.$api.target.waitExerciseNum({
         levelCode,
         subjectCode