Check for client.abort function before executing.

[graemeworthy]

line is now identical to the open() method, on #435 in the same file.

[domenic]

Can you provide a test case that fails when this check is not present?

[domenic]

Closing due to lack of response, but happy to reopen and merge if we can add a test for this.

[vincemtnz]

This blows up for me in a test (Jest) with an url variable that was undefined (so: $.get(undefined).then(...)), but the same goes for any other falsy url values.

  ● Test suite failed to run
    TypeError: client.abort is not a function

      at XMLHttpRequest.abort (node_modules/jsdom/lib/jsdom/living/xmlhttprequest.js:369:16)
      at Object.abort (node_modules/jsdom/lib/jsdom/living/xhr-utils.js:315:13)
      at RequestManager.close (node_modules/jsdom/lib/jsdom/living/nodes/Document-impl.js:146:21)
      at Window.close (node_modules/jsdom/lib/jsdom/browser/Window.js:362:29)
          at <anonymous>
      at process._tickCallback (internal/process/next_tick.js:169:7)

Firing up the debugger shows that client is an EventEmitter but does not have an abort fn. I did notice an abort fn under _events though.

[domenic]

Please open a new issue following the issue template; in particular pay attention to the instructions about a minimal example, not involving other libraries like Jest.