Use of [] with http.STATUS_CODES call.

Hi Grant,

You're right that the brackets are needed because it is an object.

Here's the documentation for http.STATUS_CODES: https://nodejs.org/api/http.html#http_http_status_codes

It gives an example of how you would access the "404" property to retrieve the "Not Found" description.

If you go into your node repl you can type http.STATUS_CODES to see what it looks like.

Here's a snippet of it: (I've deleted some lines to keep it short)

> http.STATUS_CODES
{ '100': 'Continue',
  '101': 'Switching Protocols',
  '102': 'Processing',
  '200': 'OK',
...
  '404': 'Not Found',
...
  '507': 'Insufficient Storage',
  '508': 'Loop Detected',
  '509': 'Bandwidth Limit Exceeded',
  '510': 'Not Extended',
  '511': 'Network Authentication Required' }

The codes are the properties and the values are short descriptions of that code.

There are 2 ways that properties of an object can be accessed. Using dot notation and bracket notation.

The following shows both ways:

> var person = {"name": "Grant"}
undefined
> person.name
'Grant'
> person["name"]
'Grant'
>

Dot notation can only be used when the property is a valid identifier.

We can't use dot notation for the status codes because those properties are numbers and identifiers can't begin with numbers. This won't work http.STATUS_CODES.404.

In this case, bracket notation has to be used. This will work http.STATUS_CODES["404"]

Also, if the code was stored in a variable then bracket notation would have to be used.

> var code = 404
undefined
> http.STATUS_CODES[code] // this works
'Not Found'
> http.STATUS_CODES.code // doesn't work. This is looking for a property that's literally named "code"
undefined
>

This MDN page goes into more detail on accessing properties: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Property_Accessors