Question

我是reactjs的新手，并且正在关注udemy的基础课程。我在控制台日志中收到以下错误。任何人都可以帮我吗？。

bundle.js:21818 Uncaught TypeError: _this2.props.selectBook is not a function

任何帮助将不胜感激。感谢。

容器/书list.js

import React, { Component } from 'react';
import { connect } from 'react-redux';
import { selectBook } from '../actions/index';
import { bindActionCreators } from 'redux';

class BookList extends Component {
    renderList() {
        return this.props.books.map((book) => {
            return (
                <li 
                    key={book.title} 
                    onClick={() => this.props.selectBook(book)} 
                    className="list-group-item">
                    {book.title}
                </li>
            );
        });
    }

    render() {
        return (
            <ul className="list-group col-sm-4">
                {this.renderList()}
            </ul>
        )
    }
}


function mapStateToProps(state) {
    return {
        books: state.books
    };
}

//Anythin returned from this function will end up as props
// on the BookList container
function mapDispatchToProps(dispatch) {
    // whenever selectBook is called, the result should be passed
    // to all of our reducers
    return bindActionCreators({ selectBook: selectBook }, dispatch);
}

// Promote BookList from a component to a container - it needs to know 
// about this new dispatch method, selectBook. Make it available
// as a prop.
export default connect(mapStateToProps)(BookList);

操作/ index.js

export function selectBook(book) {
    console.log('A book has been selected:', book.title);
}

组件/ app.js

import React, { Component } from 'react';

import BookList from '../containers/book-list';

export default class App extends Component {
  render() {
    return (
      <div>
        <BookList />
      </div>
    );
  }
}

Answer 1

自己找到答案。

// didnt have included the mapDispatchToProps function call in below lines.
export default connect(mapStateToProps, mapDispatchToProps)(BookList);

Answer 2

使用import selectBook from '../actions/index'代替import { selectBook } from '../actions/index';

Answer 3

确保导出selectBook操作，以便它可以在应用程序中使用

export function selectBook() {...}

Answer 4

对于已经包含mapDispatchToProps函数调用的人，即export default connect(mapStateToProps, mapDispatchToProps)(BookList);

浏览action / index.js，查看是否使用默认导出。如果不是，则在导入selectBook时需要{}左右。

if (using default export) { 

    import selectBook from '../actions/index';
}
else {

    import { selectBook } from '../actions/index';
}

干杯。

未捕获的TypeError：_this2.props.selectBook不是函数

4 个答案: