getusermedia.js

// getUserMedia helper by @HenrikJoreteg used for navigator.getUserMedia shim
var adapter = require('webrtc-adapter');

module.exports = function (constraints, cb) {
    var error;
    var haveOpts = arguments.length === 2;
    var defaultOpts = {video: true, audio: true};

    var denied = 'PermissionDeniedError';
    var altDenied = 'PERMISSION_DENIED';
    var notSatisfied = 'ConstraintNotSatisfiedError';

    // make constraints optional
    if (!haveOpts) {
        cb = constraints;
        constraints = defaultOpts;
    }

    // treat lack of browser support like an error
    if (typeof navigator === 'undefined' || !navigator.getUserMedia) {
        // throw proper error per spec
        error = new Error('MediaStreamError');
        error.name = 'NotSupportedError';

        // keep all callbacks async
        return setTimeout(function () {
            cb(error);
        }, 0);
    }

    // normalize error handling when no media types are requested
    if (!constraints.audio && !constraints.video) {
        error = new Error('MediaStreamError');
        error.name = 'NoMediaRequestedError';

        // keep all callbacks async
        return setTimeout(function () {
            cb(error);
        }, 0);
    }

    navigator.mediaDevices.getUserMedia(constraints)
    .then(function (stream) {
        cb(null, stream);
    }).catch(function (err) {
        var error;
        // coerce into an error object since FF gives us a string
        // there are only two valid names according to the spec
        // we coerce all non-denied to "constraint not satisfied".
        if (typeof err === 'string') {
            error = new Error('MediaStreamError');
            if (err === denied || err === altDenied) {
                error.name = denied;
            } else {
                error.name = notSatisfied;
            }
        } else {
            // if we get an error object make sure '.name' property is set
            // according to spec: http://dev.w3.org/2011/webrtc/editor/getusermedia.html#navigatorusermediaerror-and-navigatorusermediaerrorcallback
            error = err;
            if (!error.name) {
                // this is likely chrome which
                // sets a property called "ERROR_DENIED" on the error object
                // if so we make sure to set a name
                if (error[denied]) {
                    err.name = denied;
                } else {
                    err.name = notSatisfied;
                }
            }
        }

        cb(error);
    });
};