[elpa] 10/46: js2-parse-array-literal: improve trailing comma warning

[Dmitry Gutov]

dgutov pushed a commit to branch master
in repository elpa.

commit bce0ad0962c108dead720937749848f4adda2539
Author: Dmitry Gutov <address@hidden>
Date:   Wed May 21 04:02:22 2014 +0300

    js2-parse-array-literal: improve trailing comma warning
    
    * Only warn when language version is < 1.7.
    * Handle nil elements.
    
    Fixes #142
---
 js2-mode.el     |   13 ++++++++-----
 tests/parser.el |    3 +++
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/js2-mode.el b/js2-mode.el
index 2eb3605..f2b9802 100644
--- a/js2-mode.el
+++ b/js2-mode.el
@@ -3477,7 +3477,10 @@ You can tell the quote type by looking at the first 
character."
 
 (defun js2-print-array-node (n i)
   (insert (js2-make-pad i) "[")
-  (js2-print-list (js2-array-node-elems n))
+  (let ((elems (js2-array-node-elems n)))
+    (js2-print-list elems)
+    (when (and elems (null (car (last elems))))
+      (insert ",")))
   (insert "]"))
 
 (defstruct (js2-object-node
@@ -9257,14 +9260,14 @@ array-literals, array comprehensions and regular 
expressions."
             (= tt js2-EOF))  ; prevent infinite loop
         (if (= tt js2-EOF)
             (js2-report-error "msg.no.bracket.arg" nil pos))
+        (when (and after-comma (< js2-language-version 170))
+          (js2-parse-warn-trailing-comma "msg.array.trailing.comma"
+                                         pos (remove nil elems) after-comma))
         (setq continue nil
               pn (make-js2-array-node :pos pos
                                       :len (- js2-ts-cursor pos)
                                       :elems (nreverse elems)))
-        (apply #'js2-node-add-children pn (js2-array-node-elems pn))
-        (when (and after-comma (not js2-is-in-destructuring))
-          (js2-parse-warn-trailing-comma "msg.array.trailing.comma"
-                                         pos elems after-comma)))
+        (apply #'js2-node-add-children pn (js2-array-node-elems pn)))
        ;; destructuring binding
        (js2-is-in-destructuring
         (push (if (or (= tt js2-LC)
diff --git a/tests/parser.el b/tests/parser.el
index ee56087..a4e2e82 100644
--- a/tests/parser.el
+++ b/tests/parser.el
@@ -87,6 +87,9 @@ the test."
 (js2-deftest-parse empty-array-literal
   "c = [];")
 
+(js2-deftest-parse array-with-missing-elements
+  "var a = [1, 2, ,];")
+
 (js2-deftest-parse comma-after-regexp
   "d = /eee/, 42;")