diff --git a/lisp/progmodes/js.el b/lisp/progmodes/js.el
index 5a4f383..c0e5655 100644
--- a/lisp/progmodes/js.el
+++ b/lisp/progmodes/js.el
@@ -52,6 +52,7 @@
(require 'imenu)
(require 'moz nil t)
(require 'json nil t)
+(require 'sgml-mode)
(eval-when-compile
(require 'cl-lib)
@@ -551,6 +552,18 @@ don't indent the first one's initializer; otherwise, indent it.
:safe 'symbolp
:group 'js)
+(defcustom js-indent-jsx nil
+ "Non-nil to indent JSX elements.
+
+`sgml-basic-offset' and `sgml-attribute-offset' determine the
+indentation level of lines containing JSX.
+
+Enabling this may slow down indentation of entire large files."
+ :version "25.1"
+ :type 'boolean
+ :safe 'booleanp
+ :group 'js)
+
;;; KeyMap
(defvar js-mode-map
@@ -1998,9 +2011,195 @@ indentation is aligned to that column."
(+ js-indent-level js-expr-indent-offset))
(t 0))))
-(defun js-indent-line ()
+;;; JSX Indentation
+
+(defsubst js--jsx-find-before-tag ()
+ "Find where JSX starts.
+
+Assume JSX appears in the following instances:
+- Inside parentheses, when returned or as the first argument
+ to a function, and after a newline
+- When assigned to variables or object properties, but only
+ on a single line
+- As the N+1th argument to a function
+
+This is an optimized version of (re-search-backward \"[(,]\n\"
+nil t), except set point to the end of the match. This logic
+executes up to the number of lines in the file, so it should be
+really fast to reduce that impact."
+ (let (pos)
+ (while (and (> (point) (point-min))
+ (not (progn
+ (end-of-line 0)
+ (when (or (eq (char-before) 40) ; (
+ (eq (char-before) 44)) ; ,
+ (setq pos (1- (point))))))))
+ pos))
+
+(defconst js--jsx-end-tag-re
+ (concat "" sgml-name-re ">\\|/>")
+ "Find the end of a JSX element.")
+
+(defconst js--jsx-after-tag-re "[),]"
+ "Find where JSX ends.
+This complements the assumption of where JSX appears from
+`js--jsx-before-tag-re', which see.")
+
+(defun js--jsx-indented-element-p ()
+ "Determine if/how the current line should be indented as JSX.
+
+Return `first' for the first JSXElement on its own line.
+Return `nth' for subsequent lines of the first JSXElement.
+Return `expression' for an embedded JS expression.
+Return `after' for anything after the last JSXElement.
+Return nil for non-JSX lines.
+
+Currently, JSX indentation supports the following styles:
+
+- Single-line elements (indented like normal JS):
+
+ var element =
;
+
+- Multi-line elements (enclosed in parentheses):
+
+ function () {
+ return (
+
+
+
+ );
+ }
+
+- Function arguments:
+
+ React.render(
+ ,
+ document.querySelector('.root')
+ );"
+ (let ((current-pos (point))
+ (current-line (line-number-at-pos))
+ last-pos
+ before-tag-pos before-tag-line
+ tag-start-pos tag-start-line
+ tag-end-pos tag-end-line
+ after-tag-line
+ parens paren type)
+ (save-excursion
+ (and
+ ;; Determine if we're inside a jsx element
+ (progn
+ (end-of-line)
+ (while (and (not tag-start-pos)
+ (setq last-pos (js--jsx-find-before-tag)))
+ (while (forward-comment 1))
+ (when (= (char-after) 60) ; <
+ (setq before-tag-pos last-pos
+ tag-start-pos (point)))
+ (goto-char last-pos))
+ tag-start-pos)
+ (progn
+ (setq before-tag-line (line-number-at-pos before-tag-pos)
+ tag-start-line (line-number-at-pos tag-start-pos))
+ (and
+ ;; A "before" line which also starts an element begins with js, so
+ ;; indent it like js
+ (> current-line before-tag-line)
+ ;; Only indent the jsx lines like jsx
+ (>= current-line tag-start-line)))
+ (cond
+ ;; Analyze bounds if there are any
+ ((progn
+ (while (and (not tag-end-pos)
+ (setq last-pos (re-search-forward js--jsx-end-tag-re nil t)))
+ (while (forward-comment 1))
+ (when (looking-at js--jsx-after-tag-re)
+ (setq tag-end-pos last-pos)))
+ tag-end-pos)
+ (setq tag-end-line (line-number-at-pos tag-end-pos)
+ after-tag-line (line-number-at-pos after-tag-line))
+ (or (and
+ ;; Ensure we're actually within the bounds of the jsx
+ (<= current-line tag-end-line)
+ ;; An "after" line which does not end an element begins with
+ ;; js, so indent it like js
+ (<= current-line after-tag-line))
+ (and
+ ;; Handle another case where there could be e.g. comments after
+ ;; the element
+ (> current-line tag-end-line)
+ (< current-line after-tag-line)
+ (setq type 'after))))
+ ;; They may not be any bounds (yet)
+ (t))
+ ;; Check if we're inside an embedded multi-line js expression
+ (cond
+ ((not type)
+ (goto-char current-pos)
+ (end-of-line)
+ (setq parens (nth 9 (syntax-ppss)))
+ (while (and parens (not type))
+ (setq paren (car parens))
+ (cond
+ ((and (>= paren tag-start-pos)
+ ;; Curly bracket indicates the start of an embedded expression
+ (= (char-after paren) 123) ; {
+ ;; The first line of the expression is indented like sgml
+ (> current-line (line-number-at-pos paren))
+ ;; Check if within a closing curly bracket (if any)
+ ;; (exclusive, as the closing bracket is indented like sgml)
+ (cond
+ ((progn
+ (goto-char paren)
+ (ignore-errors (let (forward-sexp-function)
+ (forward-sexp))))
+ (< current-line (line-number-at-pos)))
+ (t)))
+ ;; Indicate this guy will be indented specially
+ (setq type 'expression))
+ (t (setq parens (cdr parens)))))
+ t)
+ (t))
+ (cond
+ (type)
+ ;; Indent the first jsx thing like js so we can indent future jsx things
+ ;; like sgml relative to the first thing
+ ((= current-line tag-start-line) 'first)
+ ('nth))))))
+
+(defmacro js--as-sgml (&rest body)
+ "Execute BODY as if in sgml-mode."
+ `(with-syntax-table sgml-mode-syntax-table
+ (let (forward-sexp-function
+ parse-sexp-lookup-properties)
+ ,@body)))
+
+(defun js--expression-in-sgml-indent-line ()
+ "Indent the current line as JavaScript or SGML (whichever is farther)."
+ (let* (indent-col
+ (savep (point))
+ ;; Don't whine about errors/warnings when we're indenting.
+ ;; This has to be set before calling parse-partial-sexp below.
+ (inhibit-point-motion-hooks t)
+ (parse-status (save-excursion
+ (syntax-ppss (point-at-bol)))))
+ ;; Don't touch multiline strings.
+ (unless (nth 3 parse-status)
+ (setq indent-col (save-excursion
+ (back-to-indentation)
+ (if (>= (point) savep) (setq savep nil))
+ (js--as-sgml (sgml-calculate-indent))))
+ (if (null indent-col)
+ 'noindent
+ ;; Use whichever indentation column is greater, such that the sgml
+ ;; column is effectively a minimum
+ (setq indent-col (max (js--proper-indentation parse-status)
+ (+ indent-col js-indent-level)))
+ (if savep
+ (save-excursion (indent-line-to indent-col))
+ (indent-line-to indent-col))))))
+
+(defun js--indent-line-as-js ()
"Indent the current line as JavaScript."
- (interactive)
(let* ((parse-status
(save-excursion (syntax-ppss (point-at-bol))))
(offset (- (point) (save-excursion (back-to-indentation) (point)))))
@@ -2008,6 +2207,29 @@ indentation is aligned to that column."
(indent-line-to (js--proper-indentation parse-status))
(when (> offset 0) (forward-char offset)))))
+(defun js-indent-line ()
+ "Indent the current line as JavaScript or JSX source text.
+If `js-indent-jsx' is non-nil, which see, indent the current line
+as JSX source text."
+ (interactive)
+ (cond
+ (js-indent-jsx
+ (let ((indentation-type (js--jsx-indented-element-p)))
+ (cond
+ ((eq indentation-type 'expression)
+ (js--expression-in-sgml-indent-line))
+ ((or (eq indentation-type 'first)
+ (eq indentation-type 'after))
+ ;; Don't treat this first thing as a continued expression (often a "<" or
+ ;; ">" causes this misinterpretation)
+ (cl-letf (((symbol-function #'js--continued-expression-p) 'ignore))
+ (js--indent-line-as-js)))
+ ((eq indentation-type 'nth)
+ (js--as-sgml (sgml-indent-line)))
+ (t (js--indent-line-as-js)))))
+ (t
+ (js--indent-line-as-js))))
+
;;; Filling
(defvar js--filling-paragraph nil)
diff --git a/test/indent/js-indent-jsx.js b/test/indent/js-indent-jsx.js
new file mode 100644
index 0000000..1ea65ed
--- /dev/null
+++ b/test/indent/js-indent-jsx.js
@@ -0,0 +1,84 @@
+var foo = ;
+
+return (
+
+);
+
+// Local Variables:
+// indent-tabs-mode: nil
+// js-indent-level: 2
+// js-indent-jsx: t
+// End:
+
+// The following test has intentionally unclosed elements and should
+// be placed below all other tests to prevent awkward indentation.
+
+return (
+