andrew310 · August 3, 2016 21:52 · Aug 3, 2016
diff --git a/dedupe.js b/dedupe.js
@@ -0,0 +1,25 @@
+var list = [1, 4, 8, 33, 2, 1, 5, 7, 8, 6, 3, 2];
+
+/*VERSION 1 */
+//retains current order of the list
+var dups = {}; //create an object, purpose is we want keys
+
+var uniques = list.filter(function(item){
+  return dups.hasOwnProperty(item) ? false : dups[item] = true;
+});
+/* How does this work?
+/  So we are using javascript objects as maps here. As you go through the list, the filter function passes the callback function each item
+/  in the list to see if it should retain that item in the filtered list. If the item is not in the dups map, we add that key to the dups
+/  map (dups[item] = true) and then return true so that this item will be retained in the list.
+/  if the key is found in the dups map, the callback function returns false, and this current item is tossed from the list.
+*/
+
+/*VERSION 2*/
+//does NOT retain current order. This is basically the same as the ES6 "set" function, also in Python.
+var sortedUniques = list.sort(function(a, b){return a-b;}).filter(function(item, pos, arr){
+  return !pos || item != arr[pos - 1];
+})
+/* How does it work?
+/  the filter function basically checks if the current item is the same as the one before it. (This works because it is sorted).
+/  if it is the same, it is tossed from the list. If not, it returns true because of the or statement, so it is retained.
+/*