Tern auto-complete won't start automatically

Question

When I enter "pars" in Emacs js-mode buffer and type tern-ac-complete, I get the desired result: list of completion candidates + the documentation next to the candidate.

However, I cannot get Tern completion to be triggered automatically. The ac-auto-start is set to 3 and the auto-complete works as expected for other cases (my dictionary file, the words I already typed in, jquery-doc, etc.)

Answer 1

The issue is that tern does not provide an ac-source yet. From the comments in tern-auto-complete.el

This program does not provide an ac-source for arbitrary timing yet.

Answer 2

This happens because tern-emacs has to request completions from tern-server (an async operation). Only when the server returns it goes on to call auto-complete with the tern sources only.

I fixed it by advising auto-complete to wait for tern request if a custom variable is set to t. This way you can get tern completions to show in your normal auto-complete workflow.

Here is the pull request (or just the diff) I made to the tern repo.

I'm adding this here in case someone stumbles here through search as i did.

Answer 3

You should try company-mode with the third-party company-tern.

It starts completion automatically with no problems.

Answer 4

Call function 'edebug-defun for function 'ac-start of auto-complete.el, and follow call trace to figure out what causes this problem.

In my case, variable 'ac-use-dictionary-as-stop-words was t and having many words on my auto completion dictionary, so auto-complete was aborted.

tern.el          : Version: 0.0.1
auto-complete.el : Version: 1.4.0 

line. 1559 (ac-abort)) ;; <= This was called!!!

$ node --version # v0.11.13-pre (on Linux)