未捕获的ReferenceError:未定义handleClick - React

Question

我会直截了当地说.这是我在ReactJS应用程序中的组件:

class BooksList extends Component {

  constructor(props) {
    super(props);
    this.handleClick = this.handleClick.bind(this);

  }

  handleClick() {
    e.preventDefault();
    console.log("The link was clicked");
  }

  render() {
    return (
      <div>
        <a className="btn btn-success" onClick={handleClick}>
            Add to cart
        </a>
      </div>
    );
  }
}

为什么在加载组件时会出现以下错误？

Uncaught ReferenceError: handleClick is not defined

编辑:

你回答后我改变了我的代码:

  handleClick(e) {
    e.preventDefault();
    console.log("Item added to the cart");
  }


  renderBooks(){
      return this.props.myBooks.data.map(function(book){
          return (
                  <div className="row">
                    <table className="table-responsive">
                      <tbody>
                        <tr>
                          <td>
                            <p className="bookTitle">{book.title}</p>
                          </td>
                        </tr>
                        <tr>
                          <td>                                  
                             <button value={book._id} onClick={this.handleClick}>Add to cart</button>
                          </td>
                        </tr>
                      </tbody>
                    </table>
                  </div>
          );
      });
    }
  }

render() {
    return (
      <div>
        <div>
          <h3>Buy our books</h3>
              {this.renderBooks()}
        </div>
      </div>
    );
  }

如你所见,我有.map一个遍历书籍列表.对于每本书,我都有一个按钮,如果单击该按钮,则会将特定的书添加到用户的购物车中.

如果我按照@Tharaka Wijebandara回答我可以让按钮在外面工作.map但在这种情况下我仍然会收到错误:

Uncaught (in promise) TypeError: Cannot read property 'handleClick' of undefined
    at http://localhost:8080/bundle.js:41331:89
    at Array.map (native)

Answer 1

使用 this.handleClick

<a className="btn btn-success" onClick={this.handleClick}>
  Add to cart
</a>

而你忘e了在你的handleClick方法中添加一个参数.

handleClick(e) {
  e.preventDefault();
  console.log("The link was clicked");
}