我在這裏寫了一個示例應用程序來讓我的頭在React中,但我的一個簡單組件拋出一個我似乎無法跟蹤的錯誤。我的渲染方法在這裏有什麼問題?
Error: Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: undefined. You likely forgot to export your component from the file it's defined in. Check the render method of
ContactListItem
.
下面是ContactListItem組件的代碼。
import React, { Component } from 'react';
import { ListGroupItem } from 'react-bootstrap';
import { Link } from 'react-router';
class ContactListItem extends Component {
render() {
const { contact } = this.props;
return (
<ListGroupItem>
<Link to={'/contact/${contact.id'}>
<h4>{contact.name}</h4>
</Link>
</ListGroupItem>
);
}
}
export default ContactListItem;
這是一個非常簡單的類。沒有任何東西可以成爲問題。爲了完成,這裏是父組件。
import React, { Component } from 'react';
import { ListGroup } from 'react-bootstrap';
import ContactActions from '../actions/ContactActions';
import ContactStore from '../stores/ContactStore';
import ContactListItem from './ContactListItem';
function getContactListItem(contact) {
return (
<ContactListItem key={contact.id} contact={contact} />
);
}
class ContactsComponent extends Component {
constructor() {
super();
this.state = {
contacts: []
}
this.onChange = this.onChange.bind(this);
}
componentWillMount() {
ContactStore.addChangeListener(this.onChange);
}
componentDidMount() {
ContactActions.receiveContacts()
}
componentWillUnmount() {
ContactStore.removeChangeListener(this.onChange);
}
onChange() {
this.setState({
contacts: ContactStore.getContacts()
});
}
render() {
let contactListItems;
if (this.state.contacts) {
contactListItems = this.state.contacts.map(contact => getContactListItem(contact));
}
return (
<div>
<ListGroup>
{contactListItems}
</ListGroup>
</div>
);
}
}
export default ContactsComponent;
您是否嘗試過使用非空'contacts'數組? – Mahdi