Merge pull request #3 from kabeh2/closure

kabeh2 · web-flow · commit 199f34711c16 · 2018-12-26T19:29:51.000-05:00
Completed closure problems
diff --git a/assignments/closure.js b/assignments/closure.js
@@ -1,20 +1,69 @@
 // ==== Challenge 1: Write your own closure ====
 // Write a simple closure of your own creation.  Keep it simple!
 
+function addNumbers() {
+  // Local free variable
+  let x = 1;
+
+  function sumNumbers() {
+    let y = 2;
+    console.log(`The new sum is: ${x + y}`);
+  }
+
+  // Here shows the global variable can be manipulated outside the environment record
+  x++;
+
+  return sumNumbers;
+}
+
+let z = addNumbers();
+z();
 
 // ==== Challenge 2: Create a counter function ====
 const counter = () => {
   // Return a function that when invoked increments and returns a counter variable.
+
+  let counter = 0;
+
+  function countUp() {
+    counter++;
+    console.log(`The new count is: ${counter}`);
+  }
+
+  return countUp;
 };
+
 // Example usage: const newCounter = counter();
 // newCounter(); // 1
 // newCounter(); // 2
 
+let plusCounter = counter();
+plusCounter();
+plusCounter();
+
 /* STRETCH PROBLEM, Do not attempt until you have completed all previous tasks for today's project files */
 
 // ==== Challenge 3: Create a counter function with an object that can increment and decrement ====
 const counterFactory = () => {
   // Return an object that has two methods called `increment` and `decrement`.
   // `increment` should increment a counter variable in closure scope and return it.
   // `decrement` should decrement the counter variable and return it.
+  let counter = 0;
+  return {
+    increment: function() {
+      let result = counter++;
+      return result;
+    },
+    decrement: function() {
+      let result = counter--;
+      return result;
+    }
+  };
 };
+
+let number = counterFactory();
+number.increment();
+number.increment();
+number.increment();
+number.decrement();
+console.log(`The new stretch number count is: ${number.increment()}`);
