Emacs major mode for .svelte files. It's based on mhtml-mode. It requires (>= emacs-major-version 26).

• MELPA

  M-x package-install RET svelte-mode RET

• Manually

  git clone https://github.com/leafOfTree/svelte-mode --depth 1

  ; ~/.emacs
  (add-to-list 'load-path "/path/to/svelte-mode")
  (require 'svelte-mode)

  For Spacemacs, put them inside dotspacemacs/user-config.

  ; ~/.spacemacs
  (defun dotspacemacs/user-config ()
        
      (add-to-list 'load-path "/path/to/svelte-mode")
      (require 'svelte-mode)

Svelte-mode should be auto enabled for .svelte files if everything goes well. Please stay up to date. Feel free to open an issue or a pull request.

This major mode includes JavaScript/CSS as submode in html-mode.

Supports

• Svelte directives and blocks.
• emmet-mode HTML/CSS detection.
• typescript-mode in <script lang="ts">...</script>
• sass-mode in <style lang="sass">...</style>.
• pug-mode in <template lang="pug">...</template>.
• coffee-mode in <script lang="coffee">...</script>.

M-x customize-set-variable RET <variable-name> RET

Or customize variable programatically, like

(customize-set-variable 'svelte-basic-offset 2)

See detail by M-x describe-variable RET <variable-name> RET.

SGML mode, which svelte-mode is derived from, automatically closes your current tag for you with the C-c C-e shortcut (sgml-close-tag). This however does not work for components that share their name with unclosed html tags, like for example the Link component from svelte-routing. SGML mode by default checks whether tags are supposed to be closed or not by comparing tag names with lists of element names case-insensitively, so <Link> is equivalent to <link>. The following configuration snippet makes the comparison of tag names by SGML mode case-sensitive when svelte-mode is the current active major-mode in the buffer. Just add it to your config file and you're good to go.

(defun svelte-mode-sgml-empty-tag-p-advice (old-function tag-name)
  "Advice function intended to wrap around `sgml-empty-tag-p

Makes case significant when checking whether tags need to be
closed or not, to not confuse elements with Svelte components."
  (if (eq major-mode 'svelte-mode)
      (assoc-string tag-name sgml-empty-tags)
    (funcall old-function tag-name)))

(defun svelte-mode-sgml-unclosed-tag-p-advice (old-function tag-name)
  "Advice function intended to wrap around `sgml-unclosed-tag-p

Makes case significant when checking whether tags need to be
closed or not, to not confuse elements with Svelte components."
  (if (eq major-mode 'svelte-mode)
      (assoc-string tag-name sgml-unclosed-tags)
    (funcall old-function tag-name)))

(advice-add 'sgml-empty-tag-p :around 'svelte-mode-sgml-empty-tag-p-advice)
(advice-add 'sgml-unclosed-tag-p :around 'svelte-mode-sgml-unclosed-tag-p-advice)