Typescript重新连接WebSocket未能调用构造函数

ReconnectingWebSocket 我得到以下信息:

reconnecting_websocket_1.default is not a constructor

typescript代码为:

import ReconnectingWebSocket, { Options } from 'reconnecting-websocket';

export class RealtimeClient {

    private reconnectingWebSocket: ReconnectingWebSocket

    constructor(private url: string, private dispatch: IDispatcher) {}

    public connect() {
        const wsOptions: Options = {
            minReconnectionDelay: 1000,
            reconnectionDelayGrowFactor: 1.0,
            connectionTimeout: 2000,
        }
        this.reconnectingWebSocket = new ReconnectingWebSocket(this.url, [], wsOptions)
        this.reconnectingWebSocket.onmessage = this.onMessage
    }

    /* ... */
}

在运行时,chrome dev tools中生成的javascript显示 reconnecting_websocket_1 default 是未定义的,我认为这是失败的根本原因。

this.reconnectingWebSocket = new reconnecting_websocket_1.default(this.url, [], wsOptions);
this.reconnectingWebSocket.onmessage = this.onMessage;

注意:

1. 我正在编译到ES5JavaScript(通过tsconfig.json 目标
2. 我对重新连接websocket没有开发依赖性 "reconnecting-websocket": "^4.0.0-rc5"