Use flycheck for indent settings in js2-mode

Question

I'm on Emacs 25.2 with js2-mode and flycheck/eslint enabled.

Currenty pressing tab (or newline) will indent as per js2-mode-js-indent-level.

I would like for it to be dynamic to match flycheck/eslint settings

Is there a way to do this ?

Answer 1

Emacs has already facilities to parse json (eslint config in this case).

Parse config and setting indent config as js-indent-level:

(defun js2-mode-use-eslint-indent ()
  (let ((json-object-type 'hash-table)
    (json-config (shell-command-to-string (format  "eslint --print-config %s"
                               (shell-quote-argument
                            (buffer-file-name))))))
    (ignore-errors
      (setq js-indent-level
        (aref (gethash "indent" (gethash  "rules" (json-read-from-string json-config))) 1)))))

(add-hook 'js2-mode-hook #'js2-mode-use-eslint-indent)