fixed bug w/ map-keys on arrays

Author: tjmehta

chain.js

@@ -62,8 +62,7 @@ function extendChainPrototype (hideWarnings) {
 
         return this
       },
-      enumerable: false,
-      configurable: envIs('test') // hack for tests
+      enumerable: false
     })
   })
 }

map-keys.js

@@ -18,14 +18,16 @@ function mapKeys (obj, callback, thisArg) {
     throw new TypeError(callback + ' must be a function')
   }
   var objIsArray = Array.isArray(obj)
+  var mapped = objIsArray ? [] : {}
   if (objIsArray) {
-    forEach = Array.prototype.forEach.call.bind(Array.prototype.forEach)
+    obj.forEach(eachCallback)
+  } else {
+    forEach(obj, eachCallback)
   }
-  var mapped = objIsArray ? [] : {}
-  forEach(obj, function (val, key, obj) {
+  function eachCallback (val, key, obj) {
     var newKey = callback.call(thisArg, key, val, obj)
     mapped[newKey] = val
-  })
+  }
   return mapped
 }
 /**

test/test-chain.js

@@ -23,8 +23,12 @@ describe('chain', function () {
       .map(mapCb)
       .mapKeys(mapKeysCb)
       .reduce(reduceCb)
+      .keys()
+      .map(mapCb)
+      .mapKeys(mapKeysCb)
+      .reduce(reduceCb)
       .toJSON()
-    expect(output).to.deep.equal({ x: 1, y: 1 })
+    expect(output).to.deep.equal(['x', 'y'])
     done()
   })
   it('should have all methods', function (done) {