node.js - React 中 fetch 不返回数据

Question

我是 react 新手，我很难从列表中获取单本书的数据，无法通过 axios 的 get 方法传递。我认为这与网址有关，但我一直无法修复它。

这是我的代码:

export function loadBook(book){
    return dispatch  => {
        return axios.get('http://localhost:3000/api/books/book/:id').then(book => {
            dispatch(loadBookSuccess(book.data));
            console.log('through!');
        }).catch(error => {
            console.log('error');
        });
    };
}

//also tried this
export function loadBook(id){
    return dispatch  => {
        return axios.get('http://localhost:3000/api/books/book/' + {id}).then(book => {
            dispatch(loadBookSuccess(book.data));
            console.log('through!');
        }).catch(error => {
            console.log('error');
        });
    };
}

包含指向每本书的变量链接的 HTML 代码

 <div className="container">
                <h3><Link to={'/book/' + book._id}> {book.title}</Link></h3>
                <h5>Author: {book.author.first_name + ' ' + book.author.family_name}</h5>
                <h4>Summary: {book.summary}</h4>
                <BookGenre genre={genre} />
                              
            </div>
            
            

route 的链接:

<Route path="/book/:id" component={BookPage} />

编辑:书籍组件的代码

class BookPage extends React.Component{
    render(){
        const book = this.props;
        const genre = book.genre;
        console.log(book);

        return(
            <div>
            <div>
                <h3> {book.title}</h3>
                <h5>Author: {book.author.first_name + ' ' + book.author.family_name}</h5>
                <h4>Summary: {book.summary}</h4>
                <BookGenre genre={genre} />                
            </div>
        
        </div>
        );
    }
}

BookPage.propTypes = {
    book: PropTypes.object.isRequired
};

//setting the book with mapStateToProps
function mapStateToProps (state, ownProps){
    let book = {title: '', author: '', summary: '', isbn: '', genre: []};
    const bookid = ownProps.params._id;
    if(state.books.length > 0){
        book = Object.assign({}, state.books.find(book => book.id));
    }
    return {
        book: book
    };
}

function mapDispatchToProps (dispatch) {
    return {
        actions: bindActionCreators(loadBook, dispatch)
    };
}



export default connect(mapStateToProps, mapDispatchToProps)(BookPage);

Answer 1

不要这样做:-

axios.get('http://localhost:3000/api/books/book/' + {id})

You should do like this:-

axios.get(`http://localhost:3000/api/books/book/${id}`)

So your action.js might look like this:-

export function loadBook(id){
    const request = axios.get(`http://localhost:3000/api/books/book/${id}`);
    return dispatch  => {
        request.then(book => {
            dispatch(loadBookSuccess(book.data));
        }).catch(error => {
            console.log('error');
        })
    };
}

由于 id，您传递的它似乎是一个字符串，因此可以使用 ES6 模板字符串 连接它，并确保将字符串用反引号括起来。或者您可以通过 + 运算符来完成此操作，同时确保将 id 作为参数传递到 loadbook 函数中，以便您可以将其连接到您的 URL。