Reduce computational complexity of normalizing value/type/language in _valueMatch.

Author: gkellogg

lib/frame.js

@@ -603,9 +603,15 @@ function _valueMatch(pattern, value) {
   const v1 = value['@value'];
   const t1 = value['@type'];
   const l1 = value['@language'];
-  const v2 = pattern['@value'] ? [].concat(pattern['@value']) : [];
-  const t2 = pattern['@type'] ? [].concat(pattern['@type']) : [];
-  const l2 = pattern['@language'] ? [].concat(pattern['@language']) : [];
+  const v2 = pattern['@value'] ?
+    (types.isArray(pattern['@value']) ? pattern['@value'] : [pattern['@value']]) :
+    [];
+  const t2 = pattern['@type'] ?
+    (types.isArray(pattern['@type']) ? pattern['@type'] : [pattern['@type']]) :
+    [];
+  const l2 = pattern['@language'] ?
+    (types.isArray(pattern['@language']) ? pattern['@language'] : [pattern['@language']]) :
+    [];
 
   if(v2.length === 0 && t2.length === 0 && l2.length === 0) {
     return true;