Reactjs 参数的顺序导致未定义

我将道具传递到函数中，并测试该函数，以确保它收到道具。我注意到顺序会影响结果。例如，如果我切换顺序，第一个“books”可以工作，但第二个“book”表示未定义，反之亦然。为什么呢

export const saveBook = (books, book) => {
    
    //result as expected
    console.log(`This is books${books}`)
   //says undefined
    console.log(`This is book${book.book.title}`)

我通过道具的地方

渲染（）{

const allBooks=this.state.books.map（book=>(
{book.book.title}
{书。书。副标题}
作者{book.book.authors}
这个。道具。存折({
用户：this.props.auth，
书籍：this.props.auth.wishlistbooks，
书：书，书
})}
/>
))

const allBooks = this.state.books.map(book => (

    <div>
      <div>
      {book.book.title}
      {book.book.subtitle}
      Written by {book.book.authors}
    </div>
    <img alt={book.book.title} src={book.book.image} />
    <Save 
        key={book.book._id}
        saveBook = {() => this.props.saveBook({
            user: this.props.auth,
            books: this.props.auth.wishlistbooks,
            book: book.book           
        })}
    />
</div>))