js-mode: Don't indent inside a multiline string literal

* lisp/progmodes/js.el (js-indent-line): Do nothing when bol is inside
a string (https://github.com/mooz/js2-mode/issues/227).

lisp/ChangeLog

@@ -1,3 +1,8 @@
+2015-04-03  Dmitry Gutov  <dgutov@yandex.ru>
+
+	* progmodes/js.el (js-indent-line): Do nothing when bol is inside
+	a string (https://github.com/mooz/js2-mode/issues/227).
+
 2015-04-02  Stefan Monnier  <monnier@iro.umontreal.ca>
 
 	* abbrev.el (define-abbrev-table): Treat a non-string "docstring" as

lisp/progmodes/js.el

@@ -2002,7 +2002,8 @@ indentation is aligned to that column."
   (let* ((parse-status
           (save-excursion (syntax-ppss (point-at-bol))))
          (offset (- (point) (save-excursion (back-to-indentation) (point)))))
-    (indent-line-to (js--proper-indentation parse-status))
+    (unless (nth 3 parse-status)
+      (indent-line-to (js--proper-indentation parse-status)))
     (when (> offset 0) (forward-char offset))))
 
 ;;; Filling

test/indent/js.js

@@ -64,6 +64,11 @@ b +=
 baz(`http://foo.bar/${tee}`)
   .qux();
 
+`multiline string
+       contents
+  are kept
+        unchanged!`
+
 // Local Variables:
 // indent-tabs-mode: nil
 // js-indent-level: 2