[removed] How to read a hand held barcode scanner best?

Question

I\'d like to be able to scan barcodes via a hand held scanner and handle the results with Javascript.

A barcode-scanner works almost like a keyboard. It outputs the

Answer 1

OK, so here's how I did it. I set up the scanner, to add a prefix (In my case, I used Ctrl+2 or the ascii code 002 (a control code) so it couldn't easily be entered via keyboard), and an ENTER, (Feel free to change this to use something like Ctrl+3 or ascii code 003 after each barcode scan, if your barcode data may contain enters). In jQuery, I capture the keypress event, and look for the prefix. I then, capture everything into a string, and then fire a custom event, that my app can listen for. Because I'm preventing the keypress event, the user can be in a text field, and scan a barcode, which can trigger an event without affecting anything they're doing.

Additionally, each barcode has a 1 digit prefix that we use, to identify the type of barcode scanned. Examples:

• E: Employee Badge
• S: Supervisor Badge
• I: Item Number

let barcodeRead = '';
let readingBarcode = false;

let handleKeyPress = (e) => {
    if (e.keyCode === 2) {
        // Start of barcode
        readingBarcode = true;
        e.preventDefault();
        return;
    }

    if (readingBarcode) {
        e.preventDefault();

        if (e.keyCode === 13) { // Enter
            readingBarcode = false;
            const evt = $.Event('barcodeScan');
            evt.state = {
                type: barcodeRead.substr(0, 1),
                code: barcodeRead.substr(1),
            };
            $(window).trigger(evt);
            barcodeRead = '';
            return;
        }

        // Append the next key to the end of the list
        barcodeRead += e.key;
    }
}

$(window).bind('keypress', handleKeyPress);

Because of this prefix, I can now identify the type of barcode, and see if it should be handled on this page. Example:

$(window).bind('barcodeScan', (e) => {
    if (e.state.type !== 'E') {
        alert('Please scan your employee badge only!');
    } else {
        $('#employee-badge').val(e.state.code);
    }
});