问Javascript :未捕获对象:TypeError(...)不是函数

EN

import { BLE } from '@ionic-native/ble';

ionViewDidEnter() {
      console.log('ionViewDidEnter');
      this.scan();
    }

    scan() 
    {
      this.setStatus('Scanning for Bluetooth LE Devices');
      this.devices = [];  // clear list

      this.ble.scan([], 5).subscribe(
        device => this.onDeviceDiscovered(device), 
        error => this.scanError(error)
      );

      setTimeout(this.setStatus.bind(this), 5000, 'Scan complete');
    }