设置状态PubSub ReactJS和Rails

Question

我已经设置了一个PubSub事件系统，但由于某种原因，在尝试再次设置成功接收到的组件的状态时，我收到了一个Cannot read property 'items' of undefined。

我似乎无法访问this，但不确定为什么？

吊篮组件

class BasketContainer extends React.Component{
constructor() {
    super()
    this.state = {
        items: [],
        subTotal: 0,
        totalPrice: 0,
        deliveryPrice: 0
    }
}
componentWillMount() {
    this.setState( {
        items: this.props.items,
    })
}
componentDidMount() {
    this.token = PubSub.subscribe('ADD_BASKET', this.subscriber)
    this.calculateTotals();
}
componentWillUnmount() {
PubSub.unsubscribe(this.token)
}
subscriber(msg, data){
console.log(msg, data) // CONSOLE LOGS CORRECTLY :)
this.setState({
    items: this.props.items // RETURNING Cannot read property 'items' of undefined
})
}
.... bottom of file and Render ....

ProductItem组件-执行发布的位置

class ProductItem extends React.Component{
constructor() {
    super()
    this.state = { 
        name: '',
        price: 0,
        code: '',
        id: ''
    }
}
componentWillMount() {
    this.setState({
        name: this.props.data.name,
        price: this.props.data.price,
        code: this.props.data.code,
        id: this.props.data.id
    })
}
addtoBasket() {
    $.ajax({
        type: "POST",
        url: "/items",
        dataType: "json",
        data: {
            item: {
                name: this.state.name,
                price: this.state.price,
                code: this.state.code
            }
        },
        success: function(data) {
            PubSub.publish('ADD_BASKET', data); // THIS WORKS CORRECTLY
            console.log("success");
        },
        error: function () {
            console.log("error");
        }
    })
}
render(){
    let productName = this.props.data.name
    let productPrice = this.props.data.price
    let productCode = this.props.data.code
    let productImg = this.props.data.image_url
    return (
        <div className="col-xs-12 col-sm-4 product">
            <img src={productImg}/>
            <h3 className="text-center">{productName}</h3>
            <h5 className="text-center">£{productPrice}</h5>
            <div className="text-center">
                <button onClick={this.addtoBasket.bind(this)} className="btn btn-primary">Add to Basket</button>
            </div>
        </div>
    )
}

}

知道我为什么会得到Cannot read property 'items' of undefined吗？

Answer 1

我想问题出在上

    this.token = PubSub.subscribe('ADD_BASKET', this.subscriber)

应该是

    this.token = PubSub.subscribe('ADD_BASKET', this.subscriber.bind(this))