Adds experimental support for Open in GitHub

src/system/array.ts

@@ -0,0 +1,14 @@
+'use strict';
+
+export namespace Arrays {
+    export function uniqueBy<T>(array: T[], accessor: (item: T) => any, predicate?: (item: T) => boolean): T[] {
+        const uniqueValues = Object.create(null);
+        return array.filter(_ => {
+            const value = accessor(_);
+            if (uniqueValues[value]) return false;
+
+            uniqueValues[value] = accessor;
+            return predicate ? predicate(_) : true;
+        });
+    }
+}