Chaining method calls that are async with assignment can lead to problems

README.md

The first result will log undefined for the supposed deferred whereas the second will return the deferred. This is due to the resolution of the callback occurring before the assignment of the referenced variable happens. Note to reproduce this multiple times in console, a new variable will need to be used, otherwise it will seemingly pass because the deferred object already exists.

chainDeferredAssignment.js

x = $.Deferred.resolve();
window.foob = $.when(x).done(function(){console.log(1, window.foob)}); console.log('asdf');
window.fooba = $.when(x); fooba.done(function(){console.log(1, window.fooba)}); console.log('asdf');