add notes on the callback example

Ladrillo · Ladrillo · commit 8a5c05116eab · 2019-08-18T12:20:43.000+02:00
diff --git a/assignments/callbacks.js b/assignments/callbacks.js
@@ -4,24 +4,38 @@ const items = ['Pencil', 'Notebook', 'yo-yo', 'Gum'];
 
 /* 
 
-  //Given this problem: 
-  
+  // GIVEN THIS PROBLEM:
+
   function firstItem(arr, cb) {
     // firstItem passes the first item of the given array to the callback function.
   }
 
-  // Potential Solution:
+  // SOLUTION:
 
-  // Higher order function using "cb" as the call back
   function firstItem(arr, cb) {
     return cb(arr[0]);
   }
 
-  // Function invocation 
-  firstItem(items, function(first) {
-    console.log(first)
-  });
+  // NOTES ON THE SOLUTION:
+
+  // firstItem is a higher order function
+  // that uses a callback (referred to as 'cb') as its second argument.
+  // To test our solution, we will try it with a variety of callbacks.
+  // Note that callbacks might be declared separately, or inlined.
+
+  // TEST 1 (inlined callback):
+
+  firstItem(items, item => console.log(`I love my ${item}!`));
+  // "I love my Pencil!"
+
+  // TEST 2 (declaring callback previously):
+
+  function exorbitantPrice(thing) {
+    console.log(`this ${thing} costs a million dollars!`);
+  };
 
+  firstItem(items, exorbitantPrice);
+  // "this Pencil costs a million dollars!"
 */
 
 
