emacs/lisp/progmodes/typescript-ts-mode.el

;;; typescript-ts-mode.el --- tree sitter support for TypeScript  -*- lexical-binding: t; -*-

;; Copyright (C) 2022-2023 Free Software Foundation, Inc.

;; Author     : Theodor Thornhill <theo@thornhill.no>
;; Maintainer : Theodor Thornhill <theo@thornhill.no>
;; Created    : October 2022
;; Keywords   : typescript tsx languages tree-sitter

;; This file is part of GNU Emacs.

;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:
;;

;;; Code:

(require 'treesit)
(require 'js)
(eval-when-compile (require 'rx))
(require 'c-ts-common) ; For comment indent and filling.

(declare-function treesit-node-start "treesit.c")
(declare-function treesit-node-end "treesit.c")
(declare-function treesit-parser-create "treesit.c")
(declare-function treesit-query-capture "treesit.c")
(declare-function treesit-query-compile "treesit.c")

(defcustom typescript-ts-mode-indent-offset 2
  "Number of spaces for each indentation step in `typescript-ts-mode'."
  :version "29.1"
  :type 'integer
  :safe 'integerp
  :group 'typescript)

(defface typescript-ts-jsx-tag-face
  '((t . (:inherit font-lock-function-call-face)))
  "Face for HTML tags like <div> and <p> in JSX."
  :group 'typescript)

(defface typescript-ts-jsx-attribute-face
  '((t . (:inherit font-lock-constant-face)))
  "Face for HTML attributes like name and id in JSX."
  :group 'typescript)

(defvar typescript-ts-mode--syntax-table
  (let ((table (make-syntax-table)))
    ;; Taken from the cc-langs version
    (modify-syntax-entry ?_  "_"     table)
    (modify-syntax-entry ?\\ "\\"    table)
    (modify-syntax-entry ?+  "."     table)
    (modify-syntax-entry ?-  "."     table)
    (modify-syntax-entry ?=  "."     table)
    (modify-syntax-entry ?%  "."     table)
    (modify-syntax-entry ?<  "."     table)
    (modify-syntax-entry ?>  "."     table)
    (modify-syntax-entry ?&  "."     table)
    (modify-syntax-entry ?|  "."     table)
    (modify-syntax-entry ?\' "\""    table)
    (modify-syntax-entry ?\240 "."   table)
    (modify-syntax-entry ?/  ". 124b" table)
    (modify-syntax-entry ?*  ". 23"   table)
    (modify-syntax-entry ?\n "> b"  table)
    (modify-syntax-entry ?\^m "> b" table)
    (modify-syntax-entry ?$ "_" table)
    (modify-syntax-entry ?` "\"" table)
    table)
  "Syntax table for `typescript-ts-mode'.")

(defun tsx-ts-mode--indent-compatibility-b893426 ()
  "Indent rules helper, to handle different releases of tree-sitter-tsx.
Check if a node type is available, then return the right indent rules."
  ;; handle commit b893426
  (condition-case nil
      (progn (treesit-query-capture 'tsx '((jsx_fragment) @capture))
             `(((match "<" "jsx_fragment") parent 0)
               ((parent-is "jsx_fragment") parent typescript-ts-mode-indent-offset)))
    (error
     `(((match "<" "jsx_text") parent 0)
       ((parent-is "jsx_text") parent typescript-ts-mode-indent-offset)))))

(defun typescript-ts-mode--indent-rules (language)
  "Rules used for indentation.
Argument LANGUAGE is either `typescript' or `tsx'."
  `((,language
     ((parent-is "program") column-0 0)
     ((node-is "}") parent-bol 0)
     ((node-is ")") parent-bol 0)
     ((node-is "]") parent-bol 0)
     ((node-is ">") parent-bol 0)
     ((and (parent-is "comment") c-ts-common-looking-at-star)
      c-ts-common-comment-start-after-first-star -1)
     ((parent-is "comment") prev-adaptive-prefix 0)
     ((parent-is "ternary_expression") parent-bol typescript-ts-mode-indent-offset)
     ((parent-is "member_expression") parent-bol typescript-ts-mode-indent-offset)
     ((parent-is "named_imports") parent-bol typescript-ts-mode-indent-offset)
     ((parent-is "statement_block") parent-bol typescript-ts-mode-indent-offset)
     ((parent-is "switch_case") parent-bol typescript-ts-mode-indent-offset)
     ((parent-is "switch_default") parent-bol typescript-ts-mode-indent-offset)
     ((parent-is "type_arguments") parent-bol typescript-ts-mode-indent-offset)
     ((parent-is "variable_declarator") parent-bol typescript-ts-mode-indent-offset)
     ((parent-is "arguments") parent-bol typescript-ts-mode-indent-offset)
     ((parent-is "array") parent-bol typescript-ts-mode-indent-offset)
     ((parent-is "formal_parameters") parent-bol typescript-ts-mode-indent-offset)
     ((parent-is "template_string") no-indent) ; Don't indent the string contents.
     ((parent-is "template_substitution") parent-bol typescript-ts-mode-indent-offset)
     ((parent-is "object_pattern") parent-bol typescript-ts-mode-indent-offset)
     ((parent-is "object") parent-bol typescript-ts-mode-indent-offset)
     ((parent-is "object_type") parent-bol typescript-ts-mode-indent-offset)
     ((parent-is "enum_body") parent-bol typescript-ts-mode-indent-offset)
     ((parent-is "class_body") parent-bol typescript-ts-mode-indent-offset)
     ((parent-is "arrow_function") parent-bol typescript-ts-mode-indent-offset)
     ((parent-is "parenthesized_expression") parent-bol typescript-ts-mode-indent-offset)
     ((parent-is "binary_expression") parent-bol typescript-ts-mode-indent-offset)

     ,@(when (eq language 'tsx)
	 (append (tsx-ts-mode--indent-compatibility-b893426)
		 `(((node-is "jsx_closing_element") parent 0)
		   ((match "jsx_element" "statement") parent typescript-ts-mode-indent-offset)
		   ((parent-is "jsx_element") parent typescript-ts-mode-indent-offset)
		   ((parent-is "jsx_text") parent-bol typescript-ts-mode-indent-offset)
		   ((parent-is "jsx_opening_element") parent typescript-ts-mode-indent-offset)
		   ((parent-is "jsx_expression") parent-bol typescript-ts-mode-indent-offset)
		   ((match "/" "jsx_self_closing_element") parent 0)
		   ((parent-is "jsx_self_closing_element") parent typescript-ts-mode-indent-offset))))
     ;; FIXME(Theo): This no-node catch-all should be removed.  When is it needed?
     (no-node parent-bol 0))))

(defvar typescript-ts-mode--keywords
  '("!" "abstract" "as" "async" "await" "break"
    "case" "catch" "class" "const" "continue" "debugger"
    "declare" "default" "delete" "do" "else" "enum"
    "export" "extends" "finally" "for" "from" "function"
    "get" "if" "implements" "import" "in" "instanceof" "interface" "is" "infer"
    "keyof" "let" "namespace" "new" "of" "private" "protected"
    "public" "readonly" "return" "satisfies" "set" "static" "switch"
    "target" "throw" "try" "type" "typeof" "var" "void"
    "while" "with" "yield")
  "TypeScript keywords for tree-sitter font-locking.")

(defvar typescript-ts-mode--operators
  '("=" "+=" "-=" "*=" "/=" "%=" "**=" "<<=" ">>=" ">>>=" "&=" "^="
    "|=" "&&=" "||=" "??=" "==" "!=" "===" "!==" ">" ">=" "<" "<=" "+"
    "-" "*" "/" "%" "++" "--" "**" "&" "|" "^" "~" "<<" ">>" ">>>"
    "&&" "||" "!" "?.")
  "TypeScript operators for tree-sitter font-locking.")

(defun tsx-ts-mode--font-lock-compatibility-bb1f97b (language)
  "Font lock rules helper, to handle different releases of tree-sitter-tsx.
Check if a node type is available, then return the right font lock rules.
Argument LANGUAGE is either `typescript' or `tsx'."
  ;; handle commit bb1f97b
  ;; Warning: treesitter-query-capture says both node types are valid,
  ;; but then raises an error if the wrong node type is used. So it is
  ;; important to check with the new node type (member_expression)
  (condition-case nil
      (progn (treesit-query-capture language '(jsx_opening_element (member_expression) @capture))
	     '((jsx_opening_element
		[(member_expression (identifier)) (identifier)]
		@typescript-ts-jsx-tag-face)

	       (jsx_closing_element
		[(member_expression (identifier)) (identifier)]
		@typescript-ts-jsx-tag-face)

	       (jsx_self_closing_element
		[(member_expression (identifier)) (identifier)]
		@typescript-ts-jsx-tag-face)))
    (error '((jsx_opening_element
	      [(nested_identifier (identifier)) (identifier)]
	      @typescript-ts-jsx-tag-face)

	     (jsx_closing_element
	      [(nested_identifier (identifier)) (identifier)]
	      @typescript-ts-jsx-tag-face)

	     (jsx_self_closing_element
	      [(nested_identifier (identifier)) (identifier)]
	      @typescript-ts-jsx-tag-face)))))

(defun typescript-ts-mode--font-lock-settings (language)
  "Tree-sitter font-lock settings.
Argument LANGUAGE is either `typescript' or `tsx'."
  (treesit-font-lock-rules
   :language language
   :feature 'comment
   `((comment) @font-lock-comment-face)

   :language language
   :feature 'constant
   `(((identifier) @font-lock-constant-face
      (:match "\\`[A-Z_][0-9A-Z_]*\\'" @font-lock-constant-face))
     [(true) (false) (null)] @font-lock-constant-face)

   :language language
   :feature 'keyword
   `([,@typescript-ts-mode--keywords] @font-lock-keyword-face
     [(this) (super)] @font-lock-keyword-face)

   :language language
   :feature 'string
   `((regex pattern: (regex_pattern)) @font-lock-regexp-face
     (string) @font-lock-string-face
     (template_string) @js--fontify-template-string
     (template_substitution ["${" "}"] @font-lock-misc-punctuation-face))

   :language language
   :override t ;; for functions assigned to variables
   :feature 'declaration
   `((function
      name: (identifier) @font-lock-function-name-face)
     (function_declaration
      name: (identifier) @font-lock-function-name-face)
     (function_signature
      name: (identifier) @font-lock-function-name-face)

     (method_definition
      name: (property_identifier) @font-lock-function-name-face)
     (method_signature
      name: (property_identifier) @font-lock-function-name-face)
     (required_parameter (identifier) @font-lock-variable-name-face)
     (optional_parameter (identifier) @font-lock-variable-name-face)

     (variable_declarator
      name: (identifier) @font-lock-function-name-face
      value: [(function) (arrow_function)])

     (variable_declarator
      name: (identifier) @font-lock-variable-name-face)

     (enum_declaration (identifier) @font-lock-type-face)

     (extends_clause value: (identifier) @font-lock-type-face)
     ;; extends React.Component<T>
     (extends_clause value: (member_expression
                             object: (identifier) @font-lock-type-face
                             property: (property_identifier) @font-lock-type-face))

     (arrow_function
      parameter: (identifier) @font-lock-variable-name-face)

     (variable_declarator
      name: (array_pattern
             (identifier)
             (identifier) @font-lock-function-name-face)
      value: (array (number) (function)))

     (catch_clause
      parameter: (identifier) @font-lock-variable-name-face)

     ;; full module imports
     (import_clause (identifier) @font-lock-variable-name-face)
     ;; named imports with aliasing
     (import_clause (named_imports (import_specifier
                                    alias: (identifier) @font-lock-variable-name-face)))
     ;; named imports without aliasing
     (import_clause (named_imports (import_specifier
                                    !alias
                                    name: (identifier) @font-lock-variable-name-face)))

     ;; full namespace import (* as alias)
     (import_clause (namespace_import (identifier) @font-lock-variable-name-face)))

   :language language
   :feature 'identifier
   `((nested_type_identifier
      module: (identifier) @font-lock-type-face)

     (type_identifier) @font-lock-type-face

     (predefined_type) @font-lock-type-face

     (new_expression
      constructor: (identifier) @font-lock-type-face)

     (enum_body (property_identifier) @font-lock-type-face)

     (enum_assignment name: (property_identifier) @font-lock-type-face)

     (variable_declarator
      name: (identifier) @font-lock-variable-name-face)

     (for_in_statement
      left: (identifier) @font-lock-variable-name-face)

     (arrow_function
      parameters:
      [(_ (identifier) @font-lock-variable-name-face)
       (_ (_ (identifier) @font-lock-variable-name-face))
       (_ (_ (_ (identifier) @font-lock-variable-name-face)))]))

   :language language
   :feature 'property
   `((property_signature
      name: (property_identifier) @font-lock-property-name-face)
     (public_field_definition
      name: (property_identifier) @font-lock-property-name-face)

     (pair key: (property_identifier) @font-lock-property-use-face)

     ((shorthand_property_identifier) @font-lock-property-use-face))

   :language language
   :feature 'expression
   '((assignment_expression
      left: [(identifier) @font-lock-function-name-face
             (member_expression
              property: (property_identifier) @font-lock-function-name-face)]
      right: [(function) (arrow_function)]))

   :language language
   :feature 'function
   '((call_expression
      function:
      [(identifier) @font-lock-function-call-face
       (member_expression
        property: (property_identifier) @font-lock-function-call-face)]))

   :language language
   :feature 'pattern
   `((pair_pattern
      key: (property_identifier) @font-lock-property-use-face
      value: [(identifier) @font-lock-variable-name-face
              (assignment_pattern left: (identifier) @font-lock-variable-name-face)])

     (array_pattern (identifier) @font-lock-variable-name-face)

     ((shorthand_property_identifier_pattern) @font-lock-variable-name-face))

   :language language
   :feature 'jsx
   (append (tsx-ts-mode--font-lock-compatibility-bb1f97b language)
	   `((jsx_attribute (property_identifier) @typescript-ts-jsx-attribute-face)))

   :language language
   :feature 'number
   `((number) @font-lock-number-face
     ((identifier) @font-lock-number-face
      (:match "\\`\\(?:NaN\\|Infinity\\)\\'" @font-lock-number-face)))

   :language language
   :feature 'operator
   `([,@typescript-ts-mode--operators] @font-lock-operator-face
     (ternary_expression ["?" ":"] @font-lock-operator-face))

   :language language
   :feature 'bracket
   '((["(" ")" "[" "]" "{" "}"]) @font-lock-bracket-face)

   :language language
   :feature 'delimiter
   '((["," "." ";" ":"]) @font-lock-delimiter-face)

   :language language
   :feature 'escape-sequence
   :override t
   '((escape_sequence) @font-lock-escape-face)))

;;;###autoload
(define-derived-mode typescript-ts-base-mode prog-mode "TypeScript"
  "Major mode for editing TypeScript."
  :group 'typescript
  :syntax-table typescript-ts-mode--syntax-table

  ;; Comments.
  (c-ts-common-comment-setup)

  ;; Electric
  (setq-local electric-indent-chars
              (append "{}():;,<>/" electric-indent-chars))
  (setq-local electric-layout-rules
	      '((?\; . after) (?\{ . after) (?\} . before)))
  ;; Navigation.
  (setq-local treesit-defun-type-regexp
              (regexp-opt '("class_declaration"
                            "method_definition"
                            "function_declaration"
                            "lexical_declaration")))
  (setq-local treesit-defun-name-function #'js--treesit-defun-name)

  ;; Imenu (same as in `js-ts-mode').
  (setq-local treesit-simple-imenu-settings
              `(("Function" "\\`function_declaration\\'" nil nil)
                ("Variable" "\\`lexical_declaration\\'"
                 js--treesit-valid-imenu-entry nil)
                ("Class" ,(rx bos (or "class_declaration"
                                      "method_definition")
                              eos)
                 nil nil))))

;;;###autoload
(define-derived-mode typescript-ts-mode typescript-ts-base-mode "TypeScript"
  "Major mode for editing TypeScript."
  :group 'typescript
  :syntax-table typescript-ts-mode--syntax-table

  (when (treesit-ready-p 'typescript)
    (treesit-parser-create 'typescript)

    ;; Indent.
    (setq-local treesit-simple-indent-rules
                (typescript-ts-mode--indent-rules 'typescript))

    ;; Font-lock.
    (setq-local treesit-font-lock-settings
                (typescript-ts-mode--font-lock-settings 'typescript))
    (setq-local treesit-font-lock-feature-list
                '((comment declaration)
                  (keyword string escape-sequence)
                  (constant expression identifier number pattern property)
                  (function bracket delimiter)))
    (setq-local syntax-propertize-function #'typescript-ts--syntax-propertize)

    (treesit-major-mode-setup)))

(if (treesit-ready-p 'typescript)
    (add-to-list 'auto-mode-alist '("\\.ts\\'" . typescript-ts-mode)))

;;;###autoload
(define-derived-mode tsx-ts-mode typescript-ts-base-mode "TypeScript[TSX]"
  "Major mode for editing TSX and JSX documents.

This major mode defines two additional JSX-specific faces:
`typescript-ts-jsx-attribute-face' and
`typescript-ts-jsx-attribute-face' that are used for HTML tags
and attributes, respectively.

The JSX-specific faces are used when `treesit-font-lock-level' is
at least 3 (which is the default value)."
  :group 'typescript
  :syntax-table typescript-ts-mode--syntax-table

  (when (treesit-ready-p 'tsx)
    (treesit-parser-create 'tsx)

    ;; Comments.
    (setq-local comment-start "// ")
    (setq-local comment-end "")
    (setq-local comment-start-skip (rx (or (seq "/" (+ "/"))
                                           (seq "/" (+ "*")))
                                       (* (syntax whitespace))))
    (setq-local comment-end-skip
                (rx (* (syntax whitespace))
                    (group (or (syntax comment-end)
                               (seq (+ "*") "/")))))

    ;; Indent.
    (setq-local treesit-simple-indent-rules
                (typescript-ts-mode--indent-rules 'tsx))

    ;; Font-lock.
    (setq-local treesit-font-lock-settings
                (typescript-ts-mode--font-lock-settings 'tsx))
    (setq-local treesit-font-lock-feature-list
                '((comment declaration)
                  (keyword string escape-sequence)
                  (constant expression identifier jsx number pattern property)
                  (function bracket delimiter)))
    (setq-local syntax-propertize-function #'tsx-ts--syntax-propertize)

    (treesit-major-mode-setup)))

(defvar typescript-ts--s-p-query
  (when (treesit-available-p)
    (treesit-query-compile 'typescript
                           '(((regex pattern: (regex_pattern) @regexp))))))

(defvar tsx-ts--s-p-query
  (when (treesit-available-p)
    (treesit-query-compile 'tsx
                           '(((regex pattern: (regex_pattern) @regexp))
                             ((variable_declarator value: (jsx_element) @jsx))
                             ((assignment_expression right: (jsx_element) @jsx))
                             ((arguments (jsx_element) @jsx))
                             ((parenthesized_expression (jsx_element) @jsx))
                             ((return_statement (jsx_element) @jsx))))))

(defun typescript-ts--syntax-propertize (beg end)
  (let ((captures (treesit-query-capture 'typescript typescript-ts--s-p-query beg end)))
    (tsx-ts--syntax-propertize-captures captures)))

(defun tsx-ts--syntax-propertize (beg end)
  (let ((captures (treesit-query-capture 'tsx tsx-ts--s-p-query beg end)))
    (tsx-ts--syntax-propertize-captures captures)))

(defun tsx-ts--syntax-propertize-captures (captures)
  (pcase-dolist (`(,name . ,node) captures)
    (let* ((ns (treesit-node-start node))
           (ne (treesit-node-end node))
           (syntax (pcase-exhaustive name
                     ('regexp
                      (cl-decf ns)
                      (cl-incf ne)
                      (string-to-syntax "\"/"))
                     ('jsx
                      (string-to-syntax "|")))))
      (put-text-property ns (1+ ns) 'syntax-table syntax)
      (put-text-property (1- ne) ne 'syntax-table syntax))))

(if (treesit-ready-p 'tsx)
    (add-to-list 'auto-mode-alist '("\\.tsx\\'" . tsx-ts-mode)))

(provide 'typescript-ts-mode)

;;; typescript-ts-mode.el ends here