How to use @zxing/library - 10 common examples

set device(device: MediaDeviceInfo | null) {

    if (!device && device !== null) {
      throw new ArgumentException('The `device` must be a valid MediaDeviceInfo or null.');
    }

    if (this.isCurrentDevice(device)) {
      console.warn('Setting the same device is not allowed.');
      return;
    }

    if (this.isAutostarting) {
      // do not allow setting devices during auto-start, since it will set one and emit it.
      console.warn('Avoid setting a device during auto-start.');
      return;
    }

    if (!this.hasPermission) {
      console.warn('Permissions not set yet, waiting for them to be set to apply device change.');
      // this.permissionResponse

private decode(
        callbackFn: (result: Result) => any,
        retryIfNotFound: boolean = true,
        retryIfChecksumOrFormatError: boolean = true,
        once = false
    ): void {

        if (undefined === this.canvasElementContext) {
            this.prepareCaptureCanvas();
        }

        this.canvasElementContext.drawImage(this.videoElement || this.imageElement, 0, 0);

        // @note generates zone.js error when switching cameras
        const luminanceSource = new HTMLCanvasElementLuminanceSource(this.canvasElement);
        const binaryBitmap = new BinaryBitmap(new HybridBinarizer(luminanceSource));

        try {
            const result = this.readerDecode(binaryBitmap);

            callbackFn(result);

            if (!once && !!this.stream) {
                setTimeout(() => this.decodeWithDelay(callbackFn), this.timeBetweenScansMillis);
            }
        } catch (re) {

            console.log(retryIfChecksumOrFormatError, re);

            if (retryIfNotFound && Exception.isOfType(re, Exception.NotFoundException)) {
                console.warn('Not found, trying again...');

private decode(
        callbackFn: (result: Result) => any,
        retryIfNotFound: boolean = true,
        retryIfChecksumOrFormatError: boolean = true,
        once = false
    ): void {

        if (undefined === this.canvasElementContext) {
            this.prepareCaptureCanvas();
        }

        this.canvasElementContext.drawImage(this.videoElement || this.imageElement, 0, 0);

        // @note generates zone.js error when switching cameras
        const luminanceSource = new HTMLCanvasElementLuminanceSource(this.canvasElement);
        const binaryBitmap = new BinaryBitmap(new HybridBinarizer(luminanceSource));

        try {
            const result = this.readerDecode(binaryBitmap);

            callbackFn(result);

            if (!once && !!this.stream) {
                setTimeout(() => this.decodeWithDelay(callbackFn), this.timeBetweenScansMillis);
            }
        } catch (re) {

            console.log(retryIfChecksumOrFormatError, re);

            if (retryIfNotFound && Exception.isOfType(re, Exception.NotFoundException)) {
                console.warn('Not found, trying again...');

this.scanFailure = new EventEmitter();
    this.scanError = new EventEmitter();
    this.scanComplete = new EventEmitter();
    this.camerasFound = new EventEmitter();
    this.camerasNotFound = new EventEmitter();
    this.permissionResponse = new EventEmitter();
    this.hasDevices = new EventEmitter();
    this.deviceChange = new EventEmitter();

    // computed data
    this._hints = new Map();
    this.hasNavigator = typeof navigator !== 'undefined';
    this.isMediaDevicesSuported = this.hasNavigator && !!navigator.mediaDevices;

    // will start codeReader if needed.
    this.formats = [BarcodeFormat.QR_CODE];
  }

this.scanSuccess = new EventEmitter();
    this.scanFailure = new EventEmitter();
    this.scanError = new EventEmitter();
    this.scanComplete = new EventEmitter();
    this.camerasFound = new EventEmitter();
    this.camerasNotFound = new EventEmitter();
    this.permissionResponse = new EventEmitter(true);
    this.hasDevices = new EventEmitter();
    this.deviceChange = new EventEmitter();

    this._device = null;
    this._enabled = true;
    this._hints = new Map();
    this.autofocusEnabled = true;
    this.autostart = true;
    this.formats = [BarcodeFormat.QR_CODE];

    // computed data
    this.hasNavigator = typeof navigator !== 'undefined';
    this.isMediaDevicesSuported = this.hasNavigator && !!navigator.mediaDevices;
  }

set device(device: MediaDeviceInfo | null) {

    if (this.isAlreadyDefinedDevice(device)) {
      return;
    }

    // in order to change the device the codeReader gotta be reseted
    this.scannerStop();

    if (!device && device !== null) {
      throw new ArgumentException('The `device` must be a valid MediaDeviceInfo or null.');
    }

    if (!!device) {
      // starts if enabled and set the current device
      this.startScan(device);
    }
  }

set tryHarder(enable: boolean) {
    if (enable) {
      this.hints.set(DecodeHintType.TRY_HARDER, true);
    } else {
      this.hints.delete(DecodeHintType.TRY_HARDER);
    }

    // new instance with new hints.
    this.scannerRestart();
  }

if (!once && !!this.stream) {
                setTimeout(() => this.decodeWithDelay(callbackFn), this.timeBetweenScansMillis);
            }
        } catch (re) {

            console.log(retryIfChecksumOrFormatError, re);

            if (retryIfNotFound && Exception.isOfType(re, Exception.NotFoundException)) {
                console.warn('Not found, trying again...');

                this.decodeWithDelay(callbackFn);
            } else if (
                retryIfChecksumOrFormatError &&
                (
                    Exception.isOfType(re, Exception.ChecksumException) ||
                    Exception.isOfType(re, Exception.FormatException)
                )
            ) {
                console.log('Checksum or format error, trying again...', re);

                this.decodeWithDelay(callbackFn);
            }
        }
    }

const luminanceSource = new HTMLCanvasElementLuminanceSource(this.canvasElement);
        const binaryBitmap = new BinaryBitmap(new HybridBinarizer(luminanceSource));

        try {
            const result = this.readerDecode(binaryBitmap);

            callbackFn(result);

            if (!once && !!this.stream) {
                setTimeout(() => this.decodeWithDelay(callbackFn), this.timeBetweenScansMillis);
            }
        } catch (re) {

            console.log(retryIfChecksumOrFormatError, re);

            if (retryIfNotFound && Exception.isOfType(re, Exception.NotFoundException)) {
                console.warn('Not found, trying again...');

                this.decodeWithDelay(callbackFn);
            } else if (
                retryIfChecksumOrFormatError &&
                (
                    Exception.isOfType(re, Exception.ChecksumException) ||
                    Exception.isOfType(re, Exception.FormatException)
                )
            ) {
                console.log('Checksum or format error, trying again...', re);

                this.decodeWithDelay(callbackFn);
            }
        }
    }

if (!once && !!this.stream) {
                setTimeout(() => this.decodeWithDelay(callbackFn), this.timeBetweenScansMillis);
            }
        } catch (re) {

            console.log(retryIfChecksumOrFormatError, re);

            if (retryIfNotFound && Exception.isOfType(re, Exception.NotFoundException)) {
                console.warn('Not found, trying again...');

                this.decodeWithDelay(callbackFn);
            } else if (
                retryIfChecksumOrFormatError &&
                (
                    Exception.isOfType(re, Exception.ChecksumException) ||
                    Exception.isOfType(re, Exception.FormatException)
                )
            ) {
                console.log('Checksum or format error, trying again...', re);

                this.decodeWithDelay(callbackFn);
            }
        }
    }