Question

I’m just trying to get a better understanding/confirmation of function arguments
In the function seen here:

function newFunction(data, status){

would the function apply specifically to data and status variables?

I don’t quite understand how the arguments work.

Answer 1

Basic Scenario

When a function is defined, the () area is used for inputs. These inputs are mapped to what data is sent in.

function newFunction(data, status){
}
newFunction(1,2);

In this scenario, data will be assigned the value of 1, and status will be assigned the value of 2 for the scope of newFunction.

Missmatched inputs

However, it does not always directly map. If fewer arguments are sent, then the unassigned input variables become undefined.

function newFunction(data, status){
}
newFunction(1);

In this scenario, data will be assigned the value of 1, and status will be assigned the value of undefined for the scope of newFunction.

arguments object

Inside of the scope of newFunction, there is also access to the array like object called arguments.

function newFunction(data, status)
{
 var args = arguments;
}
newFunction(1);

In this scenario, the variable args will hold the arguments object. There you can check args.length to see that only 1 argument was sent. args[0] will give you that argument value, being 1 in this case.

Function object

A function can be made into an object with the new keyword. By using the new keyword on a function, a Function object is made. Once the Function object is made, this may be used to refer to the current Function object instead of the global window.

function newFunction(data,status){
 if( this instanceof newFunction ){
  //use as a Function object
  this.data = data;
 }else{
  //use as a normal function
 }
}
var myNewFunction = new newFunction(1);

In this scenario, myNewFunction now holds a reference to a Function object, and can be accessed as an object through dot notation or indexing. myNewFunction["data"] and myNewFunction.data now both hold the value of 1.