Merge remote-tracking branch 'upstream/master' into master

1 files changed, 44 insertions, 2 deletions

diff --git a/javascript.html.markdown b/javascript.html.markdown
index c466c09b..3c0e6d4f 100644
--- a/javascript.html.markdown
+++ b/javascript.html.markdown
@@ -1,7 +1,7 @@
 ---
 language: javascript
 contributors:
-    - ["Adam Brenecki", "http://adam.brenecki.id.au"]
+    - ["Leigh Brenecki", "https://leigh.net.au"]
     - ["Ariel Krakowski", "http://www.learneroo.com"]
 filename: javascript.js
 ---
@@ -188,7 +188,7 @@ someVar = myArray.pop(); // Remove last element and return it
 
 // Join all elements of an array with semicolon
 var myArray0 = [32,false,"js",12,56,90];
-myArray0.join(";") // = "32;false;js;12;56;90"
+myArray0.join(";"); // = "32;false;js;12;56;90"
 
 // Get subarray of elements from index 1 (include) to 4 (exclude)
 myArray0.slice(1,4); // = [false,"js",12]
@@ -586,6 +586,48 @@ if (Object.create === undefined){ // don't overwrite it if it exists
         return new Constructor();
     };
 }
+
+// ES6 Additions
+
+// The "let" keyword allows you to define variables in a lexical scope, 
+// as opposed to a block scope like the var keyword does.
+let name = "Billy";
+
+// Variables defined with let can be reassigned new values.
+name = "William";
+
+// The "const" keyword allows you to define a variable in a lexical scope
+// like with let, but you cannot reassign the value once one has been assigned.
+
+const pi = 3.14;
+
+pi = 4.13; // You cannot do this.
+
+// There is a new syntax for functions in ES6 known as "lambda syntax".
+// This allows functions to be defined in a lexical scope like with variables
+// defined by const and let. 
+
+const isEven = (number) => {
+    return number % 2 === 0;
+};
+
+isEven(7); // false
+
+// The "equivalent" of this function in the traditional syntax would look like this:
+
+function isEven(number) {
+    return number % 2 === 0;
+};
+
+// I put the word "equivalent" in double quotes because a function defined
+// using the lambda syntax cannnot be called before the definition.
+// The following is an example of invalid usage:
+
+add(1, 8);
+
+const add = (firstNumber, secondNumber) => {
+    return firstNumber + secondNumber;
+};
 ```
 
 ## Further Reading