Merge pull request #94 from purescript/array-semigroup-optimisation

Array semigroup optimisation
purescript · Sep 26, 2016 · 4b9fdde · 4b9fdde
2 parents 178e71d + 689e736
commit 4b9fdde
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/src/Data/Semigroup.js b/src/Data/Semigroup.js
@@ -8,6 +8,8 @@ exports.concatString = function (s1) {
 
 exports.concatArray = function (xs) {
   return function (ys) {
+    if (xs.length === 0) return ys;
+    if (ys.length === 0) return xs;
     return xs.concat(ys);
   };
 };