cspell is a command line tool and librray for spell checking code. It supports camel case checking and is really popular in VSCode, roughly 1,350,000 downloads so far.

As for Emacs, there are many options there but none of them seems working perfectly for me. But I have to say they are powerful tools.Besides wucuo is kind of cool tool as well because it supports camel case as well.

I found this cspell and it works great in VSCode and I decide to move this to Emacs. A tricky thing is it a plain checker and doesn’t help to provide correction candidates for you, but flyspell does. So it better just add a flycheck-checker rather hack on Flyspell.

Here is the code:

(with-eval-after-load 'flycheck
  (flycheck-define-checker cspell
    "Cspell checker supports camel case checking"
    :command ("cspell"
              "--config" (eval (substitute-in-file-name "$HOME/.cspell.json"))
              source-inplace)
    :error-patterns
    ((info line-start (file-name) ":" line ":" column " - "
           (message)
           line-end))
    :modes (c-mode c++-mode js2-mode rjsx-mode java-mode go-mode))
  (add-to-list 'flycheck-checkers 'cspell))

Note: If you feel lagging, you can set flycheck-idle-change-delay to 3s or remove idle-change from flycheck-check-syntax-automatically.

Furthurmore, you can customize it with cspell.json