Javascript React-Redux应用程序：“；传播不可复制实例的尝试无效“；问题

一开始，该示例应用程序工作正常。我能看见 我通过浏览器页面和数据库输入的数据。现在，我明白了 数据仅通过数据库显示，浏览器不会显示数据并获取这些数据 此外，错误：“传播不可复制数据的尝试无效。” 实例”

下面是示例代码：

projectActions.js

import {FETCH_BOOK, CREATE_BOOK, DELETE_BOOK} from '../actions/projectTypes';
import axios from 'axios';

const apiUrl = 'http://api/books';

export const createBookSuccess =  (data) => {
  return {
    type: CREATE_BOOK,
    payload: {
      _id: data._id,
      author: data.author,
      publication: data.publication,
      publisher: data.publisher
    }
  }
};

export const deleteBookSuccess = _id => {
  return {
    type: DELETE_BOOK,
    payload: {
      _id
    }
  }
};

export const fetchBook = (books) => {
  return {
    type: FETCH_BOOK,
    books
  }
};

export const createBook = ({ author, publication, publisher }) => {
  return (dispatch) => {
    return axios.post(`${apiUrl}`, {author, publication, publisher})
      .then(response => {
        dispatch(createBookSuccess(response.data))
      })
      .catch(error => {
        throw(error);
      });
  };
};

export const deleteBook = _id => {
  return (dispatch) => {
    return axios.delete(`${apiUrl}/${_id}`)
      .then(response => {
        dispatch(deleteBookSuccess(response.data))
      })
      .catch(error => {
        throw(error);
      });
  };
};

export const fetchAllBooks = () => {
  return (dispatch) => {
    return axios.get(apiUrl)
      .then(response => {
        dispatch(fetchBook(response.data))
      })
      .catch(error => {
        throw(error);
      });
  };
};

import {CREATE_BOOK, DELETE_BOOK, FETCH_BOOK} from '../actions/projectTypes';

const projectReducer = (state = [], action) => {
  switch (action.types) {
    case CREATE_BOOK:
      return [...state, action.payload];
    case DELETE_BOOK:
      let afterDelete = state.filter(book => {
        return book._id !== action.payload._id
      });
      return {
        ...state,
        state: afterDelete
      }
    case FETCH_BOOK:
      return action.books;
    default:
      return state;
  }
}

export default projectReducer;

import books from './projectReducer';
import {combineReducers} from 'redux';

const rootReducer = combineReducers({
    books: books
});

export default rootReducer;

import React from 'react';
import {connect} from 'react-redux';
import BookList from '../components/bookList';
import {deleteBook} from '../store/actions/projectActions';

const BookListElement= ({books, deleteBook}) => {
  if(!books.length) {
    return (
      <div>
        No Books
      </div>
    )
  }
  return (
    <div>
      {books.map(book => {
        return (
          <BookList book={book} deleteBook={deleteBook} key={book._id} />
        );
      })}
    </div>
  );
}

const mapStateToProps = state => {
  return {
    books: state.books
  };
};

const mapDispatchToProps = dispatch => {
  return {
    deleteBook: _id => {
      dispatch(deleteBook(_id));
    }
  };
};

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

import React from 'react';

const styles = {
  borderBottom: '2px solid #eee',
  background: '#fafafa',
  margin: '.75rem auto',
  padding: '.6rem 1rem',
  maxWidth: '500px',
  borderRadius: '7px'
};

const BookList =  ({ book: { author, publication, publisher, _id }, deleteBook }) => {
  return (
    <div style={styles} key={_id}>
      <h2>{author}</h2>
      <p>{publication}</p>
      <p>{publisher}</p>
      <button className="btn waves-effect waves-light" type="submit" name="action" onClick={() => {deleteBook(_id)}}>
        <i className="large material-icons">delete_forever</i>
      </button>
    </div>
  );
};

export default BookList;

import React, {Component} from 'react';

class BookCreate extends Component {
  state= {
    author: '',
    publication: '',
    publisher: ''
  }

  handleChange = (e) => {
    this.setState({
      [e.target.id]: e.target.value
    });
  }

  handleSubmit = (e) => {
    e.preventDefault();
    this.props.createBook(this.state)
  }

  render() {
    return (
      <div className="container">
        <form onSubmit={this.handleSubmit} className="white" autoComplete="off">
          <h5 className="grey-text text-darken-3">Create New Book</h5>
          <div className="input-field">
            <label htmlFor="author">Author</label>
            <input type="text" id="author" onChange={this.handleChange}/>
          </div>

          <div className="input-field">
            <label htmlFor="publication">Publication</label>
            <input type="text" id="publication" onChange={this.handleChange}/>
          </div>

          <div className="input-field">
            <label htmlFor="publisher">Publisher</label>
            <input type="text" id="publisher" onChange={this.handleChange}/>
          </div>

          <div className="input-field">
            <button className="btn pink lighten-1 z-depth-0">Create</button>
          </div>
        </form>
      </div>
    )
  }
}

export default BookCreate;

projectReducer.js

import {FETCH_BOOK, CREATE_BOOK, DELETE_BOOK} from '../actions/projectTypes';
import axios from 'axios';

const apiUrl = 'http://api/books';

export const createBookSuccess =  (data) => {
  return {
    type: CREATE_BOOK,
    payload: {
      _id: data._id,
      author: data.author,
      publication: data.publication,
      publisher: data.publisher
    }
  }
};

export const deleteBookSuccess = _id => {
  return {
    type: DELETE_BOOK,
    payload: {
      _id
    }
  }
};

export const fetchBook = (books) => {
  return {
    type: FETCH_BOOK,
    books
  }
};

export const createBook = ({ author, publication, publisher }) => {
  return (dispatch) => {
    return axios.post(`${apiUrl}`, {author, publication, publisher})
      .then(response => {
        dispatch(createBookSuccess(response.data))
      })
      .catch(error => {
        throw(error);
      });
  };
};

export const deleteBook = _id => {
  return (dispatch) => {
    return axios.delete(`${apiUrl}/${_id}`)
      .then(response => {
        dispatch(deleteBookSuccess(response.data))
      })
      .catch(error => {
        throw(error);
      });
  };
};

export const fetchAllBooks = () => {
  return (dispatch) => {
    return axios.get(apiUrl)
      .then(response => {
        dispatch(fetchBook(response.data))
      })
      .catch(error => {
        throw(error);
      });
  };
};

import {CREATE_BOOK, DELETE_BOOK, FETCH_BOOK} from '../actions/projectTypes';

const projectReducer = (state = [], action) => {
  switch (action.types) {
    case CREATE_BOOK:
      return [...state, action.payload];
    case DELETE_BOOK:
      let afterDelete = state.filter(book => {
        return book._id !== action.payload._id
      });
      return {
        ...state,
        state: afterDelete
      }
    case FETCH_BOOK:
      return action.books;
    default:
      return state;
  }
}

export default projectReducer;

import books from './projectReducer';
import {combineReducers} from 'redux';

const rootReducer = combineReducers({
    books: books
});

export default rootReducer;

import React from 'react';
import {connect} from 'react-redux';
import BookList from '../components/bookList';
import {deleteBook} from '../store/actions/projectActions';

const BookListElement= ({books, deleteBook}) => {
  if(!books.length) {
    return (
      <div>
        No Books
      </div>
    )
  }
  return (
    <div>
      {books.map(book => {
        return (
          <BookList book={book} deleteBook={deleteBook} key={book._id} />
        );
      })}
    </div>
  );
}

const mapStateToProps = state => {
  return {
    books: state.books
  };
};

const mapDispatchToProps = dispatch => {
  return {
    deleteBook: _id => {
      dispatch(deleteBook(_id));
    }
  };
};

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

import React from 'react';

const styles = {
  borderBottom: '2px solid #eee',
  background: '#fafafa',
  margin: '.75rem auto',
  padding: '.6rem 1rem',
  maxWidth: '500px',
  borderRadius: '7px'
};

const BookList =  ({ book: { author, publication, publisher, _id }, deleteBook }) => {
  return (
    <div style={styles} key={_id}>
      <h2>{author}</h2>
      <p>{publication}</p>
      <p>{publisher}</p>
      <button className="btn waves-effect waves-light" type="submit" name="action" onClick={() => {deleteBook(_id)}}>
        <i className="large material-icons">delete_forever</i>
      </button>
    </div>
  );
};

export default BookList;

import React, {Component} from 'react';

class BookCreate extends Component {
  state= {
    author: '',
    publication: '',
    publisher: ''
  }

  handleChange = (e) => {
    this.setState({
      [e.target.id]: e.target.value
    });
  }

  handleSubmit = (e) => {
    e.preventDefault();
    this.props.createBook(this.state)
  }

  render() {
    return (
      <div className="container">
        <form onSubmit={this.handleSubmit} className="white" autoComplete="off">
          <h5 className="grey-text text-darken-3">Create New Book</h5>
          <div className="input-field">
            <label htmlFor="author">Author</label>
            <input type="text" id="author" onChange={this.handleChange}/>
          </div>

          <div className="input-field">
            <label htmlFor="publication">Publication</label>
            <input type="text" id="publication" onChange={this.handleChange}/>
          </div>

          <div className="input-field">
            <label htmlFor="publisher">Publisher</label>
            <input type="text" id="publisher" onChange={this.handleChange}/>
          </div>

          <div className="input-field">
            <button className="btn pink lighten-1 z-depth-0">Create</button>
          </div>
        </form>
      </div>
    )
  }
}

export default BookCreate;

rootReducer.js

import {FETCH_BOOK, CREATE_BOOK, DELETE_BOOK} from '../actions/projectTypes';
import axios from 'axios';

const apiUrl = 'http://api/books';

export const createBookSuccess =  (data) => {
  return {
    type: CREATE_BOOK,
    payload: {
      _id: data._id,
      author: data.author,
      publication: data.publication,
      publisher: data.publisher
    }
  }
};

export const deleteBookSuccess = _id => {
  return {
    type: DELETE_BOOK,
    payload: {
      _id
    }
  }
};

export const fetchBook = (books) => {
  return {
    type: FETCH_BOOK,
    books
  }
};

export const createBook = ({ author, publication, publisher }) => {
  return (dispatch) => {
    return axios.post(`${apiUrl}`, {author, publication, publisher})
      .then(response => {
        dispatch(createBookSuccess(response.data))
      })
      .catch(error => {
        throw(error);
      });
  };
};

export const deleteBook = _id => {
  return (dispatch) => {
    return axios.delete(`${apiUrl}/${_id}`)
      .then(response => {
        dispatch(deleteBookSuccess(response.data))
      })
      .catch(error => {
        throw(error);
      });
  };
};

export const fetchAllBooks = () => {
  return (dispatch) => {
    return axios.get(apiUrl)
      .then(response => {
        dispatch(fetchBook(response.data))
      })
      .catch(error => {
        throw(error);
      });
  };
};

import {CREATE_BOOK, DELETE_BOOK, FETCH_BOOK} from '../actions/projectTypes';

const projectReducer = (state = [], action) => {
  switch (action.types) {
    case CREATE_BOOK:
      return [...state, action.payload];
    case DELETE_BOOK:
      let afterDelete = state.filter(book => {
        return book._id !== action.payload._id
      });
      return {
        ...state,
        state: afterDelete
      }
    case FETCH_BOOK:
      return action.books;
    default:
      return state;
  }
}

export default projectReducer;

import books from './projectReducer';
import {combineReducers} from 'redux';

const rootReducer = combineReducers({
    books: books
});

export default rootReducer;

import React from 'react';
import {connect} from 'react-redux';
import BookList from '../components/bookList';
import {deleteBook} from '../store/actions/projectActions';

const BookListElement= ({books, deleteBook}) => {
  if(!books.length) {
    return (
      <div>
        No Books
      </div>
    )
  }
  return (
    <div>
      {books.map(book => {
        return (
          <BookList book={book} deleteBook={deleteBook} key={book._id} />
        );
      })}
    </div>
  );
}

const mapStateToProps = state => {
  return {
    books: state.books
  };
};

const mapDispatchToProps = dispatch => {
  return {
    deleteBook: _id => {
      dispatch(deleteBook(_id));
    }
  };
};

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

import React from 'react';

const styles = {
  borderBottom: '2px solid #eee',
  background: '#fafafa',
  margin: '.75rem auto',
  padding: '.6rem 1rem',
  maxWidth: '500px',
  borderRadius: '7px'
};

const BookList =  ({ book: { author, publication, publisher, _id }, deleteBook }) => {
  return (
    <div style={styles} key={_id}>
      <h2>{author}</h2>
      <p>{publication}</p>
      <p>{publisher}</p>
      <button className="btn waves-effect waves-light" type="submit" name="action" onClick={() => {deleteBook(_id)}}>
        <i className="large material-icons">delete_forever</i>
      </button>
    </div>
  );
};

export default BookList;

import React, {Component} from 'react';

class BookCreate extends Component {
  state= {
    author: '',
    publication: '',
    publisher: ''
  }

  handleChange = (e) => {
    this.setState({
      [e.target.id]: e.target.value
    });
  }

  handleSubmit = (e) => {
    e.preventDefault();
    this.props.createBook(this.state)
  }

  render() {
    return (
      <div className="container">
        <form onSubmit={this.handleSubmit} className="white" autoComplete="off">
          <h5 className="grey-text text-darken-3">Create New Book</h5>
          <div className="input-field">
            <label htmlFor="author">Author</label>
            <input type="text" id="author" onChange={this.handleChange}/>
          </div>

          <div className="input-field">
            <label htmlFor="publication">Publication</label>
            <input type="text" id="publication" onChange={this.handleChange}/>
          </div>

          <div className="input-field">
            <label htmlFor="publisher">Publisher</label>
            <input type="text" id="publisher" onChange={this.handleChange}/>
          </div>

          <div className="input-field">
            <button className="btn pink lighten-1 z-depth-0">Create</button>
          </div>
        </form>
      </div>
    )
  }
}

export default BookCreate;

BookListElement.js

import {FETCH_BOOK, CREATE_BOOK, DELETE_BOOK} from '../actions/projectTypes';
import axios from 'axios';

const apiUrl = 'http://api/books';

export const createBookSuccess =  (data) => {
  return {
    type: CREATE_BOOK,
    payload: {
      _id: data._id,
      author: data.author,
      publication: data.publication,
      publisher: data.publisher
    }
  }
};

export const deleteBookSuccess = _id => {
  return {
    type: DELETE_BOOK,
    payload: {
      _id
    }
  }
};

export const fetchBook = (books) => {
  return {
    type: FETCH_BOOK,
    books
  }
};

export const createBook = ({ author, publication, publisher }) => {
  return (dispatch) => {
    return axios.post(`${apiUrl}`, {author, publication, publisher})
      .then(response => {
        dispatch(createBookSuccess(response.data))
      })
      .catch(error => {
        throw(error);
      });
  };
};

export const deleteBook = _id => {
  return (dispatch) => {
    return axios.delete(`${apiUrl}/${_id}`)
      .then(response => {
        dispatch(deleteBookSuccess(response.data))
      })
      .catch(error => {
        throw(error);
      });
  };
};

export const fetchAllBooks = () => {
  return (dispatch) => {
    return axios.get(apiUrl)
      .then(response => {
        dispatch(fetchBook(response.data))
      })
      .catch(error => {
        throw(error);
      });
  };
};

import {CREATE_BOOK, DELETE_BOOK, FETCH_BOOK} from '../actions/projectTypes';

const projectReducer = (state = [], action) => {
  switch (action.types) {
    case CREATE_BOOK:
      return [...state, action.payload];
    case DELETE_BOOK:
      let afterDelete = state.filter(book => {
        return book._id !== action.payload._id
      });
      return {
        ...state,
        state: afterDelete
      }
    case FETCH_BOOK:
      return action.books;
    default:
      return state;
  }
}

export default projectReducer;

import books from './projectReducer';
import {combineReducers} from 'redux';

const rootReducer = combineReducers({
    books: books
});

export default rootReducer;

import React from 'react';
import {connect} from 'react-redux';
import BookList from '../components/bookList';
import {deleteBook} from '../store/actions/projectActions';

const BookListElement= ({books, deleteBook}) => {
  if(!books.length) {
    return (
      <div>
        No Books
      </div>
    )
  }
  return (
    <div>
      {books.map(book => {
        return (
          <BookList book={book} deleteBook={deleteBook} key={book._id} />
        );
      })}
    </div>
  );
}

const mapStateToProps = state => {
  return {
    books: state.books
  };
};

const mapDispatchToProps = dispatch => {
  return {
    deleteBook: _id => {
      dispatch(deleteBook(_id));
    }
  };
};

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

import React from 'react';

const styles = {
  borderBottom: '2px solid #eee',
  background: '#fafafa',
  margin: '.75rem auto',
  padding: '.6rem 1rem',
  maxWidth: '500px',
  borderRadius: '7px'
};

const BookList =  ({ book: { author, publication, publisher, _id }, deleteBook }) => {
  return (
    <div style={styles} key={_id}>
      <h2>{author}</h2>
      <p>{publication}</p>
      <p>{publisher}</p>
      <button className="btn waves-effect waves-light" type="submit" name="action" onClick={() => {deleteBook(_id)}}>
        <i className="large material-icons">delete_forever</i>
      </button>
    </div>
  );
};

export default BookList;

import React, {Component} from 'react';

class BookCreate extends Component {
  state= {
    author: '',
    publication: '',
    publisher: ''
  }

  handleChange = (e) => {
    this.setState({
      [e.target.id]: e.target.value
    });
  }

  handleSubmit = (e) => {
    e.preventDefault();
    this.props.createBook(this.state)
  }

  render() {
    return (
      <div className="container">
        <form onSubmit={this.handleSubmit} className="white" autoComplete="off">
          <h5 className="grey-text text-darken-3">Create New Book</h5>
          <div className="input-field">
            <label htmlFor="author">Author</label>
            <input type="text" id="author" onChange={this.handleChange}/>
          </div>

          <div className="input-field">
            <label htmlFor="publication">Publication</label>
            <input type="text" id="publication" onChange={this.handleChange}/>
          </div>

          <div className="input-field">
            <label htmlFor="publisher">Publisher</label>
            <input type="text" id="publisher" onChange={this.handleChange}/>
          </div>

          <div className="input-field">
            <button className="btn pink lighten-1 z-depth-0">Create</button>
          </div>
        </form>
      </div>
    )
  }
}

export default BookCreate;

从“React”导入React；
从'react redux'导入{connect}；
从“../components/BookList”导入BookList；
从“../store/actions/projectActions”导入{deleteBook}；
常量BookListElement=（{books，deleteBook}）=>{
如果（！books.length）{
返回(
没有书
)
}
返回(
{books.map（book=>{
返回(
);
})}
);
}
常量mapStateToProps=状态=>{
返回{
图书：国家图书
};
};
const mapDispatchToProps=调度=>{
返回{
deleteBook:\u id=>{
调度（删除本（_id））；
}
};
};
导出默认连接(
MapStateTops，
mapDispatchToProps
)（图书目录）；

bookList.js

import {FETCH_BOOK, CREATE_BOOK, DELETE_BOOK} from '../actions/projectTypes';
import axios from 'axios';

const apiUrl = 'http://api/books';

export const createBookSuccess =  (data) => {
  return {
    type: CREATE_BOOK,
    payload: {
      _id: data._id,
      author: data.author,
      publication: data.publication,
      publisher: data.publisher
    }
  }
};

export const deleteBookSuccess = _id => {
  return {
    type: DELETE_BOOK,
    payload: {
      _id
    }
  }
};

export const fetchBook = (books) => {
  return {
    type: FETCH_BOOK,
    books
  }
};

export const createBook = ({ author, publication, publisher }) => {
  return (dispatch) => {
    return axios.post(`${apiUrl}`, {author, publication, publisher})
      .then(response => {
        dispatch(createBookSuccess(response.data))
      })
      .catch(error => {
        throw(error);
      });
  };
};

export const deleteBook = _id => {
  return (dispatch) => {
    return axios.delete(`${apiUrl}/${_id}`)
      .then(response => {
        dispatch(deleteBookSuccess(response.data))
      })
      .catch(error => {
        throw(error);
      });
  };
};

export const fetchAllBooks = () => {
  return (dispatch) => {
    return axios.get(apiUrl)
      .then(response => {
        dispatch(fetchBook(response.data))
      })
      .catch(error => {
        throw(error);
      });
  };
};

import {CREATE_BOOK, DELETE_BOOK, FETCH_BOOK} from '../actions/projectTypes';

const projectReducer = (state = [], action) => {
  switch (action.types) {
    case CREATE_BOOK:
      return [...state, action.payload];
    case DELETE_BOOK:
      let afterDelete = state.filter(book => {
        return book._id !== action.payload._id
      });
      return {
        ...state,
        state: afterDelete
      }
    case FETCH_BOOK:
      return action.books;
    default:
      return state;
  }
}

export default projectReducer;

import books from './projectReducer';
import {combineReducers} from 'redux';

const rootReducer = combineReducers({
    books: books
});

export default rootReducer;

import React from 'react';
import {connect} from 'react-redux';
import BookList from '../components/bookList';
import {deleteBook} from '../store/actions/projectActions';

const BookListElement= ({books, deleteBook}) => {
  if(!books.length) {
    return (
      <div>
        No Books
      </div>
    )
  }
  return (
    <div>
      {books.map(book => {
        return (
          <BookList book={book} deleteBook={deleteBook} key={book._id} />
        );
      })}
    </div>
  );
}

const mapStateToProps = state => {
  return {
    books: state.books
  };
};

const mapDispatchToProps = dispatch => {
  return {
    deleteBook: _id => {
      dispatch(deleteBook(_id));
    }
  };
};

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

import React from 'react';

const styles = {
  borderBottom: '2px solid #eee',
  background: '#fafafa',
  margin: '.75rem auto',
  padding: '.6rem 1rem',
  maxWidth: '500px',
  borderRadius: '7px'
};

const BookList =  ({ book: { author, publication, publisher, _id }, deleteBook }) => {
  return (
    <div style={styles} key={_id}>
      <h2>{author}</h2>
      <p>{publication}</p>
      <p>{publisher}</p>
      <button className="btn waves-effect waves-light" type="submit" name="action" onClick={() => {deleteBook(_id)}}>
        <i className="large material-icons">delete_forever</i>
      </button>
    </div>
  );
};

export default BookList;

import React, {Component} from 'react';

class BookCreate extends Component {
  state= {
    author: '',
    publication: '',
    publisher: ''
  }

  handleChange = (e) => {
    this.setState({
      [e.target.id]: e.target.value
    });
  }

  handleSubmit = (e) => {
    e.preventDefault();
    this.props.createBook(this.state)
  }

  render() {
    return (
      <div className="container">
        <form onSubmit={this.handleSubmit} className="white" autoComplete="off">
          <h5 className="grey-text text-darken-3">Create New Book</h5>
          <div className="input-field">
            <label htmlFor="author">Author</label>
            <input type="text" id="author" onChange={this.handleChange}/>
          </div>

          <div className="input-field">
            <label htmlFor="publication">Publication</label>
            <input type="text" id="publication" onChange={this.handleChange}/>
          </div>

          <div className="input-field">
            <label htmlFor="publisher">Publisher</label>
            <input type="text" id="publisher" onChange={this.handleChange}/>
          </div>

          <div className="input-field">
            <button className="btn pink lighten-1 z-depth-0">Create</button>
          </div>
        </form>
      </div>
    )
  }
}

export default BookCreate;

从“React”导入React；
常量样式={
borderBottom:'2px实心#eee'，
背景：“#fafa”，
页边距：'.75rem自动'，
填充：'.6rem 1rem'，
maxWidth:'500px'，
边界半径：“7px”
};
const BookList=（{book:{author，publication，publisher，_id}，deleteBook}）=>{
返回(
{作者}
{出版}

{publisher}

{deleteBook（_id）}}>
永远删除你
);
};
导出默认书目；

bookCreate.js

import {FETCH_BOOK, CREATE_BOOK, DELETE_BOOK} from '../actions/projectTypes';
import axios from 'axios';

const apiUrl = 'http://api/books';

export const createBookSuccess =  (data) => {
  return {
    type: CREATE_BOOK,
    payload: {
      _id: data._id,
      author: data.author,
      publication: data.publication,
      publisher: data.publisher
    }
  }
};

export const deleteBookSuccess = _id => {
  return {
    type: DELETE_BOOK,
    payload: {
      _id
    }
  }
};

export const fetchBook = (books) => {
  return {
    type: FETCH_BOOK,
    books
  }
};

export const createBook = ({ author, publication, publisher }) => {
  return (dispatch) => {
    return axios.post(`${apiUrl}`, {author, publication, publisher})
      .then(response => {
        dispatch(createBookSuccess(response.data))
      })
      .catch(error => {
        throw(error);
      });
  };
};

export const deleteBook = _id => {
  return (dispatch) => {
    return axios.delete(`${apiUrl}/${_id}`)
      .then(response => {
        dispatch(deleteBookSuccess(response.data))
      })
      .catch(error => {
        throw(error);
      });
  };
};

export const fetchAllBooks = () => {
  return (dispatch) => {
    return axios.get(apiUrl)
      .then(response => {
        dispatch(fetchBook(response.data))
      })
      .catch(error => {
        throw(error);
      });
  };
};

import {CREATE_BOOK, DELETE_BOOK, FETCH_BOOK} from '../actions/projectTypes';

const projectReducer = (state = [], action) => {
  switch (action.types) {
    case CREATE_BOOK:
      return [...state, action.payload];
    case DELETE_BOOK:
      let afterDelete = state.filter(book => {
        return book._id !== action.payload._id
      });
      return {
        ...state,
        state: afterDelete
      }
    case FETCH_BOOK:
      return action.books;
    default:
      return state;
  }
}

export default projectReducer;

import books from './projectReducer';
import {combineReducers} from 'redux';

const rootReducer = combineReducers({
    books: books
});

export default rootReducer;

import React from 'react';
import {connect} from 'react-redux';
import BookList from '../components/bookList';
import {deleteBook} from '../store/actions/projectActions';

const BookListElement= ({books, deleteBook}) => {
  if(!books.length) {
    return (
      <div>
        No Books
      </div>
    )
  }
  return (
    <div>
      {books.map(book => {
        return (
          <BookList book={book} deleteBook={deleteBook} key={book._id} />
        );
      })}
    </div>
  );
}

const mapStateToProps = state => {
  return {
    books: state.books
  };
};

const mapDispatchToProps = dispatch => {
  return {
    deleteBook: _id => {
      dispatch(deleteBook(_id));
    }
  };
};

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

import React from 'react';

const styles = {
  borderBottom: '2px solid #eee',
  background: '#fafafa',
  margin: '.75rem auto',
  padding: '.6rem 1rem',
  maxWidth: '500px',
  borderRadius: '7px'
};

const BookList =  ({ book: { author, publication, publisher, _id }, deleteBook }) => {
  return (
    <div style={styles} key={_id}>
      <h2>{author}</h2>
      <p>{publication}</p>
      <p>{publisher}</p>
      <button className="btn waves-effect waves-light" type="submit" name="action" onClick={() => {deleteBook(_id)}}>
        <i className="large material-icons">delete_forever</i>
      </button>
    </div>
  );
};

export default BookList;

import React, {Component} from 'react';

class BookCreate extends Component {
  state= {
    author: '',
    publication: '',
    publisher: ''
  }

  handleChange = (e) => {
    this.setState({
      [e.target.id]: e.target.value
    });
  }

  handleSubmit = (e) => {
    e.preventDefault();
    this.props.createBook(this.state)
  }

  render() {
    return (
      <div className="container">
        <form onSubmit={this.handleSubmit} className="white" autoComplete="off">
          <h5 className="grey-text text-darken-3">Create New Book</h5>
          <div className="input-field">
            <label htmlFor="author">Author</label>
            <input type="text" id="author" onChange={this.handleChange}/>
          </div>

          <div className="input-field">
            <label htmlFor="publication">Publication</label>
            <input type="text" id="publication" onChange={this.handleChange}/>
          </div>

          <div className="input-field">
            <label htmlFor="publisher">Publisher</label>
            <input type="text" id="publisher" onChange={this.handleChange}/>
          </div>

          <div className="input-field">
            <button className="btn pink lighten-1 z-depth-0">Create</button>
          </div>
        </form>
      </div>
    )
  }
}

export default BookCreate;

import React，{Component}来自'React'；
类BookCreate扩展组件{
状态={
作者：''，
出版物：“”，
发布者：“”
}
handleChange=（e）=>{
这是我的国家({
[e.target.id]：e.target.value
});
}
handleSubmit=（e）=>{
e、 预防默认值（）；
this.props.createBook（this.state）
}
render（）{
返回(
创作新书
作者
出版
出版商
创造
)
}
}
导出默认BookCreate；

我检查了几次代码，并阅读了一篇关于这个问题的老文章 但作为一名大三学生，我没有找到任何解决办法。如果你愿意，那就太好了 说我错过了什么

---

编辑：将view.js文件添加为bookList.js。

在reducer中，状态应为数组，但在删除过程中，您返回了一个对象：

case DELETE_BOOK:
  let afterDelete = state.filter(book => {
    return book._id !== action.payload._id
  });
  return afterDelete;

---

当您试图在reducer中复制未定义的数组时，会发生此错误。 例如：

---

在本例中，“someList”未定义或不是数组。确保拼写正确，否则使用的数组正确。

我认为您应该将获取响应返回到reducer状态，并且可以在一行中过滤删除的书籍。也许这样行

//projectReducer.js
从“../actions/projectTypes”导入{CREATE_BOOK，DELETE_BOOK，FETCH_BOOK}；
const projectReducer=（状态=[]，操作）=>{
开关（动作类型）{
案例创建书：
返回[…状态、动作、有效载荷]；
案例删除书：
返回状态=状态.filter（book=>book.\u id！==action.payload.\u id）
书包：
返回状态=action.books；
违约：
返回状态；
}
}
导出默认projectReducer；

不必回答此问题，但这可能有助于收到此错误消息并无意中访问此SO帖子的人 我也犯了这个错误。在我的例子中，错误是我试图克隆的元素实际上是一个对象而不是数组

这就是我最终要做的：

var clone = {...this.state.myObj};

（代替）

---

我知道，很明显，但我们都从某个地方开始，对吗？

在哪一行有错误？@DamianPeralta我再次运行代码，现在ı没有任何错误，但数据仍然不会显示在浏览器上。但是，我可以通过数据库看到。仍然不起作用，结果显示“无书”。或者您有一个未定义的数组！一个简单的解决方法：

constnewlist=state.someList？[…state.someList]：[]