Svelte-QRCode-Image

QR-Code generated using node-qrcode and display via <img> or <canvas> element, with TypeScript support and exported as ESM, works on SvelteKit.
Visit this page for live demo.
1.0.0 coming very soon

Installation

Directly from npm:

npm install svelte-qrcode-image

From GitHub:

npm install git+https://github.com/1toldyou/svelte-qrcode-image.git

Usage

Under the <script> tag:

import { QRCodeImage } from "svelte-qrcode-image";

And that's all you need to put inside the <script> tag.

<QRCodeImage text="hi" />
<QRCodeImage text="hi" width=233 />
<QRCodeImage text="hi" width=233 height=233 />
<QRCodeImage text="hi" scale=10 displayType="canvas" />
<QRCodeImage displayType="canvas" displayStyle="border-style: dotted;" width=500 displayWidth=400 />

You can also bind the text props to a variable, and will automatically refresh when the variable changes (reactivity)

<QRCodeImage text={eee} />

for more real example you can reference the source code of the demo page.

Parameters

These parameters can be pass in to the <QRCodeImage /> Although none of them are required, but please fill in the text

prop	type	description	default value
text	string	what you want the QR Code to show; the QR Code will changed automatically if any changes in the variable binding to it	"Hello World"
displayType	"img" | "canvas"	display the image in <canvas> or <img>	"img"
displayWidth	number	pass to the width attribute of <img> or ` tag	null - the final <img> element will not have this property
displayHeight	number	pass to the height attribute of <img> or ` tag	null - the final <img> element will not have this property
displayStyle	string	pass to the style attribute of <img> or <canvas> tag	null - the final <img> element will not have this property
altText	string	pass to the alt attribute of <img> tag	"QR Code"
displayID	string	pass to the id attribute of <img> or ` tag	null - the final element will not have this property
displayClass	string	pass to the class attribute of <img> or ` tag	null - the final element will not have this property
margin	number	pass to margin to the options of qrcode: Define how much wide the quiet zone should be	4
scale	number	pass to scale to the options of qrcode: A value of 1 means 1px per modules (black dots)	4
width	number	pass to width to the options of qrcode: Forces a specific width for the output image and takes precedence over scale.	undefined - will be calculated
errorCorrectionLevel	"L" | "M" | "Q" | "H"	pass to errorCorrectionLevel to the options of qrcode: Error correction level.	"M"
version	number	pass to version to the options of qrcode: QR Code version.	undefined - will be calculated

Troubleshooting

If you encounter any problem, please open an issue on our GitHub Issue

Nevertheless, we recommend you to this with the latest version of Svelte or SvelteKit and unable to guarantee that it will work with older versions. The minimum version required of SvelteKit is 1.0.0-next.373 which use Vite 3. And not works with ancient browsers by default.

Limitation

The QR Code is being generated (A.K.A. the actual work) when onMount being called to prevent the undefined behavior of bind:this. Might only have the <img> or <canvas> tag created during SSR.

Plans

TODO

• Documentation
• Expose options to control the <img> tag
• Reactivity on text change
• Website for demo
• Display the QR-Code as canvas
• Display the QR-Code as background image
• Option to use different "backend" to generate the image
• Automatic Testing
• Reactivity on other options change (especially the size)

Dependencies

• qrcode

Change Log

See CHANGELOG.md

Developing

Once you've created a project and installed dependencies with npm install (or pnpm install or yarn), start a development server:

npm run dev

You can change the port in vite.config.ts, the default port is 3001 and can be opened in localhost:3001 or 127.0.0.1:3001

Since this being setup as SvelteKit project, so you should create your component in src/lib directory. And re-export it in src/lib/index.js file.

export { default as MyComponent } from './MyComponent.svelte';

Publish Package

Simply run this

svelte-package

will create a new directory called package with the TypeScript definition

Then you can publish it to npm (remember to login first)

cd package
npm publish

or

npm publish ./package

Publish Website

Due to recent change in SvelteKit, you need to run this command to build the website

vite build

Instead of 'npm run build` Since it's being internally linked to

svelte-kit sync && svelte-package

Which will npt create the public directory, which is needed for the website to work.

Footnote

• node-qrcode and qrcode is the same thing