重新赋值Number后显示值为空

<FormItem
          label="茶点价格"
          prop="price"
        >
          <Input
            v-model="changecakeForm.price"
            placeholder="Enter something..."
          ></Input>
        </FormItem>

changecakeForm: {
        price: null
      }

price: [
          { required: true, message: '茶点价格不能为空', trigger: 'blur' },
          {
            type: 'number',
            message: '请输入数字',
            trigger: 'blur',
            transform (value) {
              return Number(value);
            }
          }
        ],