@use-symbology-scanner

Table of contents

• Table of contents
• Introduction
• Installation
• Usage
• Options
• Symbologies
  • Standard Symbologies
  • Custom Symbologies
• Supported hardware
• Contributing
  • Development
  • Testing
  • Releasing
• License

Introduction

This package provides a simple way to listen for scanner input in the browser. It works by listening for keydown events and matching the input against a set of symbologies.

Installation

This package comes in two flavours; react and vanilla. The react package is a wrapper around the vanilla package that provides a React hook for listening to scanner input.

Vanilla

npm install @use-symbology-scanner/vanilla
yarn add @use-symbology-scanner/vanilla
pnpm add @use-symbology-scanner/vanilla

React

npm install @use-symbology-scanner/react
yarn add @use-symbology-scanner/react
pnpm add @use-symbology-scanner/react

Usage

React

import { useSymbologyScanner } from '@use-symbology-scanner/react';

export const App = () => {
    const ref = useRef(null)

    const handleSymbol = (symbol, matchedSymbologies) => {
        console.log(`Scanned ${symbol}`)
    }

    useSymbologyScanner(handleSymbol, { target: ref })

    return (
        <div ref={ref}>
        </div>
    )
}

Vanilla

<!-- index.html -->
<div id="el"></div>

// script.js
const el = document.getElementById('id')

const handleSymbol = (symbol, matchedSymbologies) => {
    console.log(`Scanned ${symbol}`)
}

const scanner = new SymbologyScanner(handleSymbol, {}, el)

scanner.destroy() // clean up listeners

Options

Property	Type	Description	Default Value
target	EventTarget	DOM element to listen for keydown events in.	window.document
symbologies	Array<Symbology, StandardSymbologyKey>	Symbologies to match against.	STANDARD_SYMBOLOGIES
enabled	boolean	Whether or not the scanner is enabled.	true
eventOptions	object	Options to pass to the addEventListener call.	{ capture: false, passive: true }
preventDefault	boolean	Whether or not to call preventDefault on the event.	false
ignoreRepeats	boolean	Whether or not to ignore repeated keydown events.	true
scannerOptions	object	Options that describe the behaviour of the hardware scanner.	{ prefix: '', suffix: '', maxDelay: 20 }

Symbologies

A Symbology is a defined method of representing numeric or alphabetic digits using bars and spaces that are easily scanned by computer systems. By default, all of the standard symbologies in the table below are matched against the input.

Standard Symbologies

Symbology	Allowed Characters	Min Length	Max Length
UPC-A	0-9	12	12
UPC-E	0-9	6	6
EAN-8	0-9	8	8
EAN 13	0-9	13	13
Codabar	0-9, -, ., $, :, /, +	4
Code 11	0-9, -	4
Code 39	0-9, A-Z, , $, %, *, +, -, ., /	1
Code 93	0-9, A-Z, , $, %, +, -, .	1
Code 128	0-9, A-Z, , $, %, *, +, -, ., /	1
Code 25 Interleaved	0-9	1
Code 25 Industrial	0-9	1
MSI Code	0-9	1
QR Code	0-9, A-Z, , $, %, *, +, -, ., /, :	1
PDF417	0-9, A-Z, , $, %, *, +, -, ., /, :	1
Data Matrix	0-9, A-Z, , $, %, *, +, -, ., /, :	1
Aztec	0-9, A-Z, , $, %, *, +, -, ., /, :	1
Dot Code	0-9, A-Z, , $, %, *, +, -, ., /, :	1

In order to only match against a subset of the standard symbologies, you can pass in an array of symbologies to the symbologies option:

import { STANDARD_SYMBOLOGY_KEYS } from '@use-symbology-scanner/core';

const symbologies = [
    STANDARD_SYMBOLOGY_KEYS['EAN-8'],
    STANDARD_SYMBOLOGY_KEYS['EAN-13'],
]

Missing a common symbology or an issue with one of the standard symbologies? Feel free to open an issue or a pull request. Alternatively, you can define your own custom symbologies.

Custom Symbologies

You can also define your own custom symbologies to match against the input.

Property	Type	Description
name	string	Name of the symbology.
allowedCharacters	RegExp	Allowed characters in the symbology.
minLength	number	Minimum length of the symbology.
maxLength	number	Maximum length of the symbology.

allowedCharacters must only contain a character class. For example, [0-9] is valid, but 0-9 is not. You can define a custom symbology like so:

import { Symbology } from '@use-symbology-scanner/core';

const customSymbology = new Symbology({
    name: 'Custom Symbology',
    allowedCharacters: '[0-9]',
    minLength: 1,
    maxLength: 10
})

Supported hardware

This library has not yet been tested on any hardware. If you have a scanner that you would like to test this library with, please open an issue or a pull request. Generally, this library should work with any hardware that emits keydown events. You can tweak the scannerOptions to match the behaviour of your hardware. For example, if your scanner emits a newline character after each scan, you can configure the scannerOptions like so:

const scannerOptions = {
    prefix: '',
    suffix: '\n',
    maxDelay: 20
}

Bluetooth scanners may require a longer maxDelay value due to latency. If you are using a bluetooth scanner, try increasing the maxDelay value to 100 or 200.

Contributing

Development

git clone
cd @use-symbology-scanner/core
yarn install
yarn build

Testing

yarn test

License

MIT