Scanner service

The scanner service provides an implementation for barcode and QR code scanning. It follows a subscription pattern where the platform can start/stop scanning and listen for scanned codes.

Registration

export default async context => {
    const listeners = [];

    context.service.addService({
        type: 'scannerService',
        start: async () => {
            // Initialize your scanner hardware
        },
        stop: async () => {
            // Release scanner resources
        },
        onCodeScanned: callback => {
            listeners.push(callback);
            // Return a cleanup function to unsubscribe
            return () => {
                listeners.splice(listeners.indexOf(callback), 1);
            };
        },
    });
};

Methods

start()

Called when the platform wants to activate the scanner. Use this to initialize your scanner hardware or begin listening for scan input.

stop()

Called when the platform wants to deactivate the scanner. Use this to release resources or stop listening for scan input.

onCodeScanned(callback)

Registers a listener that should be called whenever a code is scanned. The callback receives an object with a code property containing the scanned value.

Returns a cleanup function that removes the listener when called.

Dispatching scanned codes

When your scanner hardware detects a code, notify all registered listeners:

function onScanDetected(code) {
    for (const listener of listeners) {
        listener({ code });
    }
}