flymake-jsts: A Flymake backend for Javascript/Typescript

Supported Linters

• eslint
• oxlint
• biome

Requirements

• emacs 29+
• pfuture

Installation

(use-package flymake-jsts
  :straight '(flymake-jsts :type git :host github :repo "orzechowskid/flymake-jsts" :branch "main"))

Then enable the linter(s) of your choice:

• M-x flymake-jsts-eslint-enable (or -oxlint-enable, etc.)
• M-x flymake-mode

Configuration

useful variables are members of the flymake-jsts group and can be viewed and modified with the command M-x customize-group [RET] flymake-jsts [RET].

flymake-jsts-executable-name-alist

Mapping of linters to binary names. Useful if you want to use eslint_d instead of eslint, for instance.

flymake-jsts-project-markers-alist

Mapping of linters to 'project markers': files which denote the root of a project tree for which linting is applied. Useful if you have a config file with a weird name, so it can be found and its directory can be used as $PWD for the linter process.

flymake-jsts-show-rule-name

Non-nil to show the name of a lint rule as part of the Flymake diagnostic message, or nil to suppress.

flymake-jsts-show-extended-info

Non-nil to show extra information for each lint rule (when provided), or nil to suppress.

flymake-jsts-error-type

flymake-jsts-warning-type

Type symbols to use when reporting errors. Useful to customize if you want to distinguish Flymake errors from other sources of errors (e.g. LSP).

Others

flymake-jsts/debug

Non-nil to write tracing info to the *Messages* buffer. It sometimes comes in handy when things aren't working as expected for you.

Comparison with flymake-eslint

this is a from-the-ground-up rewrite of flymake-eslint, which was the first elisp package I ever published; I've learned a lot since then! it should be easier to add support for other linters like stylelint, for instance, and it should be a little easier to customize too.

Playbooks

Usage with eglot

Tip

tsx-mode.el can configure this (and lots more) for you.

eglot is pretty aggressive in taking over your Flymake configuration; it assumes that your language server is the only source of diagnostic messages, and completely overwrites the value of flymake-diagnostic-functions to suit its own needs. One workaround you can try is to add a flymake-jsts backend function after eglot has been enabled:

(add-hook 'eglot-managed-mode-hook
  (lambda ()
    (flymake-jsts-eslint-enable))
  nil t)

Alternately, you can tell eglot to stay out of your Flymake configuration and then add eglot's backend yourself:

(add-to-list 'eglot-stay-out-of 'flymake)
(add-hook 'flymake-mode-hook
  (lambda ()
    (add-hook 'flymake-diagnostic-functions
	  #'eglot-flymake-backend
	  nil
	  t)))

License

GPLv3