You can declare functions with "function". You need to add the parentheses in order to invoke the function. You can assign a function to a variable. Which means that you can assign a single function to multiple variables. You can create a function with the Function class constructor. You can pass parameters or arguments to a function. You can also access parameters via the arguments object. You can assign default values to parameters if none are passed. You can access a variable number of parameters with the spread operator. You can simulated named parameters by passing an object. You should assign an empty object by default to avoid errors. You can specify defaults for named parameters.