Angular 6中的socket.io-stream导入问题

npm install socket.io-stream

import * as io from 'socket.io-client';
import * as ss from 'socket.io-stream';

import { NgModule } from '@angular/core';
import { SocketIoModule, SocketIoConfig } from 'ngx-socket-io';

const config: SocketIoConfig = { url: 'http://localhost:3000', options: {} };

@NgModule({
  imports: [
    SocketIoModule.forRoot(config)
  ],
  declarations: [AppComponent],
  bootstrap: [AppComponent]
})
export class AppModule { }

import { Component } from '@angular/core';
import * as io from 'socket.io-client';
import * as ss from 'socket.io-stream';

@Component({
  selector: 'app-root',
  template: `
    <button (click)="sendFile()">Send File</button>
  `
})
export class AppComponent {
  private socket: any;

  constructor() {
    this.socket = io('http://localhost:3000');
  }

  sendFile() {
    const stream = ss.createStream();
    const fileReader = new FileReader();

    fileReader.onload = (event: any) => {
      const arrayBuffer = event.target.result;
      const buffer = new Uint8Array(arrayBuffer);

      ss(this.socket).emit('file', stream, { size: buffer.length });
      ss.createBlobReadStream(buffer).pipe(stream);
    };

    fileReader.readAsArrayBuffer(file);
  }
}