finished callbacks.js

clem9281 · clem9281 · commit ea6cd4b6c822 · 2019-01-22T13:25:18.000-07:00
diff --git a/assignments/callbacks.js b/assignments/callbacks.js
@@ -1,6 +1,6 @@
 // Create a callback function and invoke the function to test your work. You have been provided an example of a problem and a solution to see how this works with our items array.  Study both the problem and the solution to figure out the rest of the problems.
 
-const items = ['Pencil', 'Notebook', 'yo-yo', 'Gum'];
+const items = ["Pencil", "Notebook", "yo-yo", "Gum"];
 
 /* 
 
@@ -21,32 +21,89 @@ const items = ['Pencil', 'Notebook', 'yo-yo', 'Gum'];
 
 */
 
-
 function getLength(arr, cb) {
   // getLength passes the length of the array into the callback.
+  return cb(arr);
 }
+console.log(
+  getLength(items, function(array) {
+    return array.length;
+  })
+);
 
 function last(arr, cb) {
   // last passes the last item of the array into the callback.
+  return cb(arr[arr.length - 1]);
 }
+console.log(
+  last(items, function(lastItem) {
+    return lastItem;
+  })
+);
 
 function sumNums(x, y, cb) {
   // sumNums adds two numbers (x, y) and passes the result to the callback.
+  return cb(x + y);
 }
+console.log(
+  sumNums(1, 2, function(num) {
+    return num;
+  })
+);
 
 function multiplyNums(x, y, cb) {
   // multiplyNums multiplies two numbers and passes the result to the callback.
+  return cb(x * y);
 }
+console.log(
+  multiplyNums(1, 2, function(num) {
+    return num;
+  })
+);
 
 function contains(item, list, cb) {
   // contains checks if an item is present inside of the given array/list.
   // Pass true to the callback if it is, otherwise pass false.
+  return cb(list.includes(item));
 }
+console.log(
+  contains("Gum", items, function(bool) {
+    return bool;
+  })
+);
 
 /* STRETCH PROBLEM */
+let listWithDuplicates = [
+  "one",
+  "one",
+  "three",
+  "two",
+  "two",
+  "three",
+  "three",
+  "five",
+  "tree",
+  "four",
+  "five",
+  "five",
+  "five"
+];
 
 function removeDuplicates(array, cb) {
   // removeDuplicates removes all duplicate values from the given array.
   // Pass the duplicate free array to the callback function.
   // Do not mutate the original array.
+  return cb(
+    array.reduce(function(acc, element) {
+      if (!acc.includes(element)) {
+        acc.push(element);
+      }
+      return acc;
+    }, [])
+  );
 }
+console.log(
+  removeDuplicates(listWithDuplicates, function(array) {
+    return array;
+  })
+);
