[VUE]TypeError: Cannot read properties of null (reading 'data')

Uncaught (in promise) TypeError: Cannot read properties of undefined (reading 'includes')

        <select v-model="selectedCategory">

          <option :key="index" v-for="(data,index) in selectItems" :value="data">{{ data.title }}</option>

        </select>

        <p>{{ selectedCategory.data }}</p>

---

        else if (newExpanded[0].includes("Duplicated"))

        {

          this.assetCodeInfo=[{ASSET_CODE: this.Category[0]}];

          this.clickedHistoryDate=[];

          //아래 넘어가지 않도록 return으로 끝내기

          return;

        }

---

          :class="{ deleted: item.IS_DELETED}"

i tried this. but
TypeError: Cannot read properties of null (reading 'data')
is yelling like this.

solutions

add a condtion. Like under.

        <p v-if="selectedCategory">{{ selectedCategory.type }}</p>

---

        else if (newExpanded[0]&& newExpanded[0].includes("Duplicated"))

        {

          this.assetCodeInfo=[{ASSET_CODE: this.Category[0]}];

          this.clickedHistoryDate=[];

          //아래 넘어가지 않도록 return으로 끝내기

          return;

        }

---

      return Array.isArray(this.assetCodeInfo) ? this.assetCodeInfo.filter(entry=>entry.UPDATE_DATE===this.clickedHistoryDate):[];

---

          :class="{ deleted: item && item.IS_DELETED }"

 

---

but why? it like a java's try, catch?s