do the excercises in callbacks.js

ropeks · ropeks · commit 51ae38157d93 · 2019-05-07T15:38:17.000+02:00
diff --git a/assignments/callbacks.js b/assignments/callbacks.js
@@ -27,25 +27,57 @@ const items = ['Pencil', 'Notebook', 'yo-yo', 'Gum'];
 
 function getLength(arr, cb) {
   // getLength passes the length of the array into the callback.
+  return cb(arr.length);
 }
 
+getLength(items, function(len){
+  console.log(len)
+});
+
+
 function last(arr, cb) {
   // last passes the last item of the array into the callback.
+  return cb(arr[arr.length - 1]);
 }
 
+last(items, function(l){
+  console.log(l)
+});
+
 function sumNums(x, y, cb) {
   // sumNums adds two numbers (x, y) and passes the result to the callback.
+  return cb(x+y);
 }
 
+sumNums(2, 3, function(r){
+  console.log(r)
+});
+
 function multiplyNums(x, y, cb) {
   // multiplyNums multiplies two numbers and passes the result to the callback.
+  return cb(x*y);
 }
 
+multiplyNums(2, 3, function(r){
+  console.log(r)
+});
+
 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.
+  let truthness = false;
+  for (let i = 0; i < list.length; i++){
+    if (list[i] === item){
+      truthness = true;
+    }
+  }
+  return cb(truthness);
 }
 
+contains("yo-yo", items, function(r){
+  console.log(r)
+});
+
 /* STRETCH PROBLEM */
 
 function removeDuplicates(array, cb) {
