我正在使用useFieldArray从我的后端API获取默认值。我的类别是一个字符串数组。但是，Reaction-Hook-Form只支持对象数组。这是我的 Mongoose 的图式

type BookDocument = Document & {
  title: string
  description: string
  categories: string[]
  language: string
  publicationYear: number
}

const bookSchema = new Schema(
  {
    title: { type: String, required: true },
    description: { type: String, required: true },
    categories: [{ type: String, requried: true }],
    language: { type: String, required: true },
    publicationYear: { type: Number, required: true },
  },
  { timestamps: true }
)

因此，我不得不从前台修改我的表单如下：

type FormData = {
  title: string
  description: string
  categories: { category: string }[]
  language: string
  year: number
}

 const {
    handleSubmit,
    control,
    formState: { errors },
  } = useForm<FormData>({
    mode: 'onBlur',
    defaultValues: {
      title: book.title ?? '',
      description: book.description ?? '',
      categories:
        book.categories.map((elem) => {
          return { category: elem }
        }) ?? '',
      language: book.language ?? '',
      year: book.publicationYear ?? '',
    },
  })

问题是什么时候调用API请求。网络有效负载将如下所示，因此无法发送到后端