vue element编辑框根据值动态确认是否是必填项required true or false问题

<el-form-item label="生产日期" prop="manufacture_date"
  :rules="editRuleForm.manufacture_date === null">
      <el-date-picker
          v-model="editRuleForm.manufacture_date"
          type="date"
          :value-format="'yyyy-MM-dd'"
          placeholder="生产日期"
          >
      </el-date-picker>
</el-form-item>
<el-form-item label="失效日期" prop="expire_date"
 :rules="editRuleForm.expire_date === null">
      <el-date-picker
          v-model="editRuleForm.expire_date"
          type="date"
          :value-format="'yyyy-MM-dd'"
          placeholder="失效日期">
      </el-date-picker>
</el-form-item>

:rules="editRuleForm.manufacture_date === null"

<script>
	export default {
		data() {
			return {
				editRuleForm: {}, //修改表单数据
				editRules: {
					manufacture_date: [
				    {required: true, message: "请输入生产日期", trigger: "blur"},
				    ],
				    expire_date: [
				      {required: true, message: "请输入失效日期", trigger: "blur"},
				    ],
				}
			}
	}