When should I name things with initial capital letters?

Question

I have always wondered when to use identifiers (for example, functions) with capital first letter instead of camel case. I always write my JS in camel case like this:

function doStuff() {}  var simpleVar = 'some stuff',     myAry = [],     myObj = {}; 

... But I know I am supposed to name some things with capital first letters. I just don't know WHEN this rule applies. Hope somebody can make things a bit clearer to me.

Answer 1

According to the book "Javascript: the good parts", you should only capitalise the first character of the name of a function when you need to construct the object by "new" keyword.

This is called "the Constructor Invocation Pattern", a way to inherits.

Answer 2

The convention is to name constructor functions (i.e. functions that will be used with the new keyword) with starting capital.

function MyType(simpleVar) {     this.simpleVar = simpleVar; }  myObject = new MyType(42);