fix(javascript) final solid fix for runaway regex

Author: joshgoebel

CHANGES.md

@@ -18,6 +18,9 @@ New Languages:
 
 Language Improvements:
 
+- fix(r) fixed keywords not properly spaced (#2852) [Josh Goebel][]
+- fix(javascript) fix potential catastrophic backtracking (#2852) [Josh Goebel][]
+- fix(livescript) fix potential catastrophic backtracking (#2852) [Josh Goebel][]
 - bug(xml) XML grammar was far too imprecise/fuzzy [Josh Goebel][]
 - enh(xml) Improve precision to prevent false auto-detect positives [Josh Goebel][]
 - fix(js/ts) Prevent for/while/if/switch from falsly matching as functions (#2803) [Josh Goebel][]

src/languages/javascript.js

@@ -256,9 +256,7 @@ export default function(hljs) {
           regex.lookahead(regex.concat(
             // we also need to allow for multiple possible comments inbetween
             // the first key:value pairing
-            /(\/\/.*$)*/,
-            /(\/\*(.|\n)*\*\/)*/,
-            /\s*/,
+            /(((\/\/.*$)|(\/\*(\*[^/]|[^*])*\*\/))\s*)*/,
             IDENT_RE + '\\s*:'))),
         relevance: 0,
         contains: [