Simple qr/barcode scanning with svelte and Html5Qrcode

#javascript #svelte

Ever wanted to scan qr and barcodes using your mobile but didn't want to write a full blown native app just to get camera access?

Use your mobile browser! Html5 now supports it.

Open the demo in your mobile browser - chrome, safari, firefox all worked for me!

Honestly, I couldn't believe how easy it was! Check out the code:

<script>
    import { Html5Qrcode } from 'html5-qrcode'
    import { onMount } from 'svelte'

    let scanning = false

    let html5Qrcode

    onMount(init)

    function init() {
        html5Qrcode = new Html5Qrcode('reader')
    }

    function start() {
        html5Qrcode.start(
            { facingMode: 'environment' },
            {
                fps: 10,
                qrbox: { width: 250, height: 250 },
            },
            onScanSuccess,
            onScanFailure
        )
        scanning = true
    }

    async function stop() {
        await html5Qrcode.stop()
        scanning = false
    }

    function onScanSuccess(decodedText, decodedResult) {
        alert(`Code matched = ${decodedText}`)
        console.log(decodedResult)
    }

    function onScanFailure(error) {
        console.warn(`Code scan error = ${error}`)
    }
</script>

<style>
    main {
        display: flex;
        flex-direction: column;
        align-items: center;
        justify-content: center;
        gap: 20px;
    }
    reader {
        width: 100%;
        min-height: 500px;
        background-color: black;
    }
</style>

<main>
    <reader id="reader"/>
    {#if scanning}
        <button on:click={stop}>stop</button>
    {:else}
        <button on:click={start}>start</button>
    {/if}
</main>