use array as default value for ensureArray

lib/array.js

@@ -9,7 +9,7 @@ const checkArray = val => {
 module.exports = {
     toArray: arraylike => [...arraylike],
 
-    ensureArray: val => Array.isArray(val) ? val : [val],
+    ensureArray: (val = []) => Array.isArray(val) ? val : [val],
 
     head (ar) {
         checkArray(ar);

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@mightyplow/jslib",
-  "version": "0.6.0",
+  "version": "0.6.1",
   "description": "js, helpers library",
   "main": "jslib.js",
   "devDependencies": {