Attempt to capture frames of video from the camera using the 'objc' bridge module

capture.js

const objc = require('objc');
const ffi = require('ffi');

objc.import('AVFoundation');

const {
    AVCaptureDevice,
    AVCaptureDeviceInput,
    AVCaptureSession,
    AVCaptureSessionPreset640x480,
    AVCaptureVideoDataOutput,
    AVMediaTypeVideo,
    kCVPixelBufferPixelFormatTypeKey
} = objc;

const c = new ffi.Library(null, {
    dispatch_queue_create: ['pointer', ['string', 'pointer']]
});

// list attached devices
let devices = objc.js(AVCaptureDevice.devices());

devices.forEach(device => {
    let name = objc.js(device.localizedName());
    console.log(name);
});

// capture some frames
let captureSession = AVCaptureSession.alloc().init();
captureSession.sessionPreset = AVCaptureSessionPreset640x480;

let captureDevice = AVCaptureDevice.defaultDeviceWithMediaType_(
    AVMediaTypeVideo
);

const error = objc.allocRef();
let videoInput = AVCaptureDeviceInput.deviceInputWithDevice_error_(
    captureDevice,
    error
);

captureSession.addInput_(videoInput);

let videoDataOutput = AVCaptureVideoDataOutput.alloc().init();
captureSession.addOutput_(videoDataOutput);

const AVCaptureVideoDataOutputSampleBufferDelegate = objc.createClass(
    'AVCaptureVideoDataOutputSampleBufferDelegate',
    'NSObject',
    {
        'captureOutput:didOutputSampleBuffer:fromConnection:': (
            self,
            cmd,
            captureOutput,
            sampleBuffer,
            connection
        ) => {
            console.log(
                '-[AVCaptureVideoDataOutputSampleBufferDelegate captureOutput:didOutputSampleBuffer:fromConnection:]'
            );
            return 1;
        },

        _encodings: {
            'captureOutput:didOutputSampleBuffer:fromConnection:': [
                'v40',
                ['@0', ':8', '@16', '@24', '@32']
            ]
        }
    }
);

const delegate = AVCaptureVideoDataOutputSampleBufferDelegate.new();

//dispatch_queue_t queue = dispatch_queue_create("myQueue", NULL);

let queue = c.dispatch_queue_create('myQueue', null);

// videoDataOutput.videoSettings = objc.ns({
//     kCVPixelBufferPixelFormatTypeKey: 'BGRA'
// }, [hint = '@'])

videoDataOutput.setSampleBufferDelegate_queue_(delegate, queue);

captureSession.startRunning();

console.log(error);

console.log('hey');

setTimeout(() => {
    console.log('end');
}, 10000);

fyi, the objc.js call in line 21 is unnecessary. you can use a for ... of loop to iterate over NSArray, NSDictionary and NSSet instances:

for (const device of AVCaptureDevice.devices()) {
    console.log(`${device.localizedName()}`);
}