1 files changed, 30 insertions, 0 deletions
diff --git a/lib/internal/filter.js b/lib/internal/filter.js
new file mode 100644
index 0000000..8b1de9f
--- /dev/null
+++ b/lib/internal/filter.js
@@ -0,0 +1,30 @@
+'use strict';
+
+import arrayMap from 'lodash/_arrayMap';
+import property from 'lodash/_baseProperty';
+
+export default function _filter(eachfn, arr, iterator, callback) {
+    var results = [];
+    eachfn(arr, function (x, index, callback) {
+        iterator(x, function (err, v) {
+            if (err) {
+                callback(err);
+            }
+            else {
+                if (v) {
+                    results.push({index: index, value: x});
+                }
+                callback();
+            }
+        });
+    }, function (err) {
+        if (err) {
+            callback(err);
+        }
+        else {
+            callback(null, arrayMap(results.sort(function (a, b) {
+                return a.index - b.index;
+            }), property('value')));
+        }
+    });
+}