Extended Parameter Handling Another nice set of features introduced in ES6 is the extended parameter handling. These provide a very nice set of idioms that bring us very close to languages like C# or Java. Default parameter values and optional parameters Default parameters allow your functions to have optional arguments without needing to check arguments.length or check for undefined. Let’s take a look at what that might look like: let greet = (msg = 'hello', name = 'world') => { console.log(msg,name); } greet(); greet('hey'); Looking at the preceding code, you can see that we are using the new fat arrow (=>) syntax as well as the new let keyword. Neither of those are necessary for this example, but I added it to give you more exposure to the new syntax. Running the preceding code produces the following result: hello world hey world Rest parameter Handling a function with a variable number of arguments is always t