未捕获的名称:无法读取React中未定义的属性‘TypeError’

Question

我正在玩Mobx-state-tree。

在我构建的一个简单模型中，我得到了这样的错误：“未捕获名称:无法读取未定义的属性‘TypeError’”。

我正在粘贴所有的代码块。

Index.js

import React,{Component} from "react";
import ReactDOM from 'react-dom';
import App from "./app";
import Invoice from "../models/Invoice"

const invoice = Invoice.create({currency:'EUR'}) ;

ReactDOM.render(<App invoice={invoice}/>,document.getElementById('root'));

app.Js

import React,{Component} from "react";
import {observer} from "mobx-react"

class App extends Component
{
    render(){
        const {invoice} = this.props;

        return(
            <div className="container-fluid">Invoicer
            <h1>{invoice.status()} </h1>
            {!invoice.isPaid && <button onClick={invoice.markPaid}>Pay</button>}
            </div>
        );
    }
}

export default observer(App);

模型/ Invoice.js

import {types} from "mobx-state-tree";
import ItemList from "./ItemList";

const Invoice  = types.model("Invoice",{
    currency : types.string,
    isPaid:false,
    itemList : types.optional(ItemList,{items:[]})
})
.actions( self => ({
    markPaid(){
     self.isPaid = true;
    }
}))
.views( self => ({

    status(){
        return self.isPaid ? "Paid,Go Home and Enjoy" :"Not Paid,work more and we will think about it";
    }
}));

export default Invoice;

ItemList.js

import {types} from "mobx-state-tree";
import {Item} from "./Item";

const ItemList = types.model("ItemList",{
    items: types.array(Item)
});

export default ItemList;

item.js

import {types} from "mobx-state-tree"

const Item = types.model("Item",{
    quantity : types.number,
    price: types.number,
    comodityName: types.string
});

export default Item;

使用npm编译时，终端没有错误。在bundle.js中，错误在此行中

 array: function(e) {
                return new nt(e.name + "[]",e)
            },

我不确定为什么会发生这个错误？