XMLHttpRequest for image data should also check for status code 0

[austinkkoehler]

Use case: description, code

When retrieving image data, dom-to-image-more checks for a status code of >=300 as a generic catch-all for errors.

The library fails when there is something that returns a status of 0, such as DNS or CORS rejection errors (among a few other things, see the answers here: https://stackoverflow.com/questions/2000609/why-is-ajax-returning-http-status-code-0).

I'm unable to provide a fix myself.

Expected behavior

XMLHttpRequest accounts for 0 as it does >=300: be considered a failure, but allow SVG conversion to continue.

Actual behavior (stack traces, console logs etc)

The request is treated as a success, so readAsDataURL fails because it attempts to operate on a null response. This is viewable through the browser's error logs.

Library version

3.4.5

Browsers

• Chrome 49+
• Firefox 45+