Avoid setting a device during auto-start.

Describe the bug When using the camera, I get an error saying: ‘Avoid setting a device during auto-start.’

To Reproduce Steps to reproduce the behavior:

1. Open a page using the camera and the <zxing-scanner> tag.

Expected behavior The feedback of the camera should appear

Desktop (please complete the following information):

• OS: MacOs Cataline 10.15.5
• Browser Chrome
• Version 84.0.4147.135

Additional context According to source code, we are setting the device during auto start:

private autostartScanner(devices: MediaDeviceInfo[]) {

    const matcher = ({ label }) => /back|trás|rear|traseira|environment|ambiente/gi.test(label);

    // select the rear camera by default, otherwise take the last camera.
    const device = devices.find(matcher) || devices.pop();

    if (!device) {
      throw new Error('Impossible to autostart, no input devices available.');
    }

    this.device = device; // HERE!
    // @note when listening to this change, callback code will sometimes run before the previous line.
    this.deviceChange.emit(device);

    this.isAutostarting = false;
    this.autostarted.next();
  }

IMPORTANT: This might help you debug my issue: I had ^3.0.0 as a package dependency. while facing the issue I was on v 3.0.1 with your latest commit. Fixing version to 3.0.0 solved my issue.

[coffeymatt]

I’ve got this working via

html:

<zxing-scanner
          #webScanner
          *ngIf="scanning"
          [(device)]="currentDevice"
          (camerasFound)="onCamerasFound($event)"
          (scanSuccess)="webScanFoundItem($event)"
          [tryHarder]="true">        
        </zxing-scanner>

and in the ts code

  availableDevices: MediaDeviceInfo[];
  currentDevice: MediaDeviceInfo = null;

  onCamerasFound(devices: MediaDeviceInfo[]): void {
    this.availableDevices = devices;

    if (this.availableDevices && this.availableDevices.length > 0) {
      this.currentDevice = this.availableDevices[0];
    }
  }

[r3plica]

If you set the autostart="false" how do you start once you have set the device? All I get is this warning:

Feature ‘autostart’ disabled. Permissions and devices recovery has to be run manually.

The permissions have been requested and accepted, what is devices recorvery?