TypeError in _trimBreadcrumbs where crumb.data exists but is undefined

[svanzoest]

What is the current behavior?

It seems to be that there is a situation where https://github.com/getsentry/raven-js/blob/3.14.0/src/raven.js#L1358-L1359

    _trimBreadcrumbs: function (breadcrumbs) {
        // known breadcrumb properties with urls
        // TODO: also consider arbitrary prop values that start with (https?)?://
        var urlprops = {to: 1, from: 1, url: 1},
            crumb,
            data;

        for (var i = 0; i < breadcrumbs.values.length; i++) {
            crumb = breadcrumbs.values[i];
>            if (!crumb.hasOwnProperty('data'))
>               continue;

            data = crumb.data;
            for (var prop in urlprops) {
>                if (data.hasOwnProperty(prop)) {
                    data[prop] = truncate(data[prop], this._globalOptions.maxUrlLength);
                }
            }
        }
    },

Does not seem to catch crumb.data where it exists but is undefined. This causes the browser to exhibit the following in my Chrome 57.0.2987.133 console.log.

Fetch API cannot load https://api.domain.com/1/resource. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'https://example.domain.com' is therefore not allowed access. The response had HTTP status code 401. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.

vendor.d6f6b2b….js:1
Uncaught TypeError: Cannot read property 'hasOwnProperty' of undefined
at i._trimBreadcrumbs (vendor.d6f6b2b….js:1)
at i._trimPacket (vendor.d6f6b2b….js:1)
at i._sendProcessedPayload (vendor.d6f6b2b….js:1)
at i._send (vendor.d6f6b2b….js:1)
at i._processException (vendor.d6f6b2b….js:1)
at i._handleStackInfo (vendor.d6f6b2b….js:1)
at i.captureException (vendor.d6f6b2b….js:1)
at a (app.3b3d78964d8bfab1c109.js:1)
at b.onunhandledrejection (app.3b3d78964d8bfab1c109.js:1)
vendor.d6f6b2b….js:1

This seems to be related to the further down the line if (data.hasOwnProperty(prop)) { which causes the Uncaught TypeError: Cannot read property 'hasOwnProperty' of undefined

This issue seems to be introduced by 3.14.0 on Chrome 57.0.2987.133 on MacOS 10.12.3 (16D32), which is build into a vendor.js via webpack2.

The expected behavior is the raven client to not cause a TypeError by tempting to access a property of an undefined object.