qrstuv

A clean and modern QR code reader for browsers. Uses Promises for returning results, rather than callbacks (Node-style or otherwise).

2011 Lazar Laszlo http://lazarsoft.info 2014 Jess Telford http://jes.st 2016 Stuart P. Bentley https://stuartpb.com/

This is a fork of a port to npm of Lazar Laszlo's port of ZXing qrcode scanner, http://code.google.com/p/zxing.

Lazar's demo exhibits basically the same functionality as this module: http://webqr.com

Prerequisites

Note that, as this library uses Promises, if you're supporting an environment that doesn't provide a native Promise implementation, you'll need to include a polyfill that provides Promise like es6-shim (for browsers) or a module that implements Promise like bluebird (for Node/Browserify).

If you're in a sandboxed module environment like Node, you'll need to explicitly introduce your Promise module to this one:

var qrcode = require('qrstuv');
qrcode.Promise = require('bluebird');

Of course, if you're using Node 4.0.0 or later, or a reasonably recent version of Google Chrome or Mozilla Firefox, you don't have to worry about this, since Promise is in the environment by default in all of these. Polyfilling promise is, essentially, a legacy concern in 2016.

Usage

qrcode = require('qrstuv');
qrcode.decode(uri).then(function(result) {
  console.log(result); // Will output the decoded information
});

If uri is not passed, will instead extract image data from a canvas element with id="qr-canvas"

[new from 2014.01.09] For webcam qrcode decoding (included in the test.html) you will need a browser with getUserMedia (WebRTC) capability.

Usage on Node

Since Node doesn't come with an implementation of Canvas or Image the way that browsers do, you'll need to introduce your own. You can do this relatively easily by installing the canvas module, which comes with both:

var qrcode = require('qrstuv');
var Canvas = require('canvas');
qrcode.Canvas = Canvas;
qrcode.Image = Canvas.Image;
 
qrcode.decode(__dirname + '/qrcode.png').then(function(result) {
  console.log(result);
}