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[](https://www.npmjs.com/package/qrcode)
[](https://www.npmjs.com/package/qrcode)
[](https://github.com/soldair/node-qrcode/blob/master/license)
# node-qrcode
> QR code/2d barcode generator.
It is an extension of "QRCode for JavaScript" which Kazuhiko Arase thankfully MIT licensed.
## Installation
Inside your project folder do:
```shell
npm install --save qrcode
```
or, install it globally to use `qrcode` from the command line to save qrcode images or generate ones you can view in your terminal.
```shell
npm install -g qrcode
```
## Dependencies
`node-canvas` is required.
(note: this dependency is only needed for server side use and will be likely removed in the future)
### Install node-canvas dependencies
`node-canvas` is a native module and requires dev packages of `Cairo` and `Pango` to compile.
Make sure to have these libs available on your system before run `npm install qrcode`
Installation instructions are available on [node-canvas](https://github.com/Automattic/node-canvas#installation) page.
## Usage
```shell
qrcode <text> [output file]
```
Output image format is detected from file extension.
Only `png` and `svg` format are supported for now.
If no output file is specified, the QR Code will be rendered directly in the terminal.
#### Example
```shell
qrcode "Draw a QR Code in my terminal"
```
```shell
qrcode "I like to save qrs as a PNG" qr.png
```
```shell
qrcode "I also like to save them as a SVG" qr.svg
```
## Client side
`node-qrcode` can be used in browser through [Browserify](https://github.com/substack/node-browserify), [Webpack](https://github.com/webpack/webpack) or by including the precompiled
bundle present in `build/` folder.
#### Browserify or Webpack
```html
<!-- index.html -->
<html>
<body>
<canvas id="canvas"></canvas>
<script src="bundle.js"></script>
</body>
</html>
```
```javascript
// index.js -> bundle.js
var QRCode = require('qrcode')
var QRCodeDraw = new QRCode.QRCodeDraw()
var canvas = document.getElementById('canvas')
QRCodeDraw.draw(canvas, 'sample text', function (error, canvas) {
if (error) console.error(error)
console.log('success!');
})
```
#### Precompiled bundle
```html
<canvas id="canvas"></canvas>
<script src="/build/qrcode.min.js"></script>
<script>
var qrcodedraw = new qrcodelib.qrcodedraw()
qrcodedraw.draw(document.getElementById('canvas'), 'sample text', function (error, canvas) {
if (error) console.error(error)
console.log('success!');
})
</script>
```
Precompiled files are generated in `build/` folder during installation.
To manually rebuild the lib run:
```shell
npm run build
```
### Methods
```javascript
draw(canvasElement, text, [optional options], cb(error, canvas));
```
##### Options
```javascript
errorCorrectLevel
```
Can be one of the values in `QRCode.errorCorrectLevel`.
If `undefined`, defaults to H which is max error correction.
## Server side API
```javascript
QRCode.draw(text, [optional options], cb(error, canvas));
```
Returns a node canvas object see https://github.com/Automattic/node-canvas for all of the cool node things you can do. Look up the canvas api for the other cool things.
```javascript
QRCode.toDataURL(text, [optional options], cb(error, dataURL));
```
Returns mime image/png data url for the 2d barcode.
```javascript
QRCode.drawSvg(text, [optional options], cb(error, svgString));
```
SVG output!
```javascript
QRCode.save(path, text, [optional options], cb(error, written));
```
Saves png to the path specified returns bytes written.
```javascript
QRCode.drawText(text, [optional options], cb)
```
Returns an ascii representation of the qrcode using unicode characters and ansi control codes for background control.
```javascript
QRCode.drawBitArray(text, [optional options], cb(error, bits, width));
```
Returns an array with each value being either 0 light or 1 dark and the width of each row.
This is enough info to render a qrcode any way you want. =)
##### Options
```javascript
errorCorrectLevel
```
Can be one of the values in `qrcode.errorCorrectLevel`.
Can be a string, one of `"minimum", "medium", "high", "max"`.
If `undefined`, defaults to H which is max error correction.
#### Example
```javascript
var QRCode = require('qrcode')
QRCode.toDataURL('I am a pony!', function (err, url) {
console.log(url)
})
```
## GS1 QR Codes
There was a real good discussion here about them. but in short any qrcode generator will make gs1 compatable qrcodes, but what defines a gs1 qrcode is a header with metadata that describes your gs1 information.
https://github.com/soldair/node-qrcode/issues/45
## License
[MIT](https://github.com/soldair/node-qrcode/blob/master/license)
The word "QR Code" is registered trademark of:
DENSO WAVE INCORPORATED