coc doesn't work with ale

[cvlmtg]

Describe the bug
If I install ale, coc stops working. completion doesn't work and :messages says

[coc.nvim] Error on InsertEnter: Cannot read property 'clearHighlight' of undefined
[coc.nvim] Error on TextChanged: Cannot read property 'filetype' of undefined
[coc.nvim] Error on TextChanged: Cannot read property 'filetype' of undefined
[coc.nvim] Error on TextChanged: Cannot read property 'filetype' of undefined

To Reproduce
Steps to reproduce the behavior:

1. Install coc.nvim with coc-tsserver and see that it is working
2. Install ale and now coc.nvim no longer works

Expected behavior
coc.nvim should not break when ale is installed

Desktop (please complete the following information):

• Terminal: kitty 0.12.3 and tmux
• Version: nvim v0.3.2-797-g500345aea

[chemzqm]

I'm using coc.nvim and ale as well, but I can't reproduce this problem.

[cvlmtg]

I'll try to set up a minimal config with a clean install and see if it depends on some of my configuration, however I'm not sure I'll be able to have some spare time soon. meanwhile thanks for fixing coc-eslint, now this problem is not urgent anymore :)

[chemzqm]

When the current document is null you'll get errors like these, it was fixed at d56d961.
Reopen this issue if you still get these messages.