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Mastering JavaScript Design Patterns by Simon Timms

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Objects in JavaScript

JavaScript is an object-oriented language, but most people don't make use of the object-oriented features of it except in passing. JavaScript uses a mixed object model in that it has some primatives as well as objects. JavaScript has five primitive types:

  • Undefined
  • Null
  • Boolean
  • String
  • Number

Of these five, really only three of them are what one would expect to be an object anyway. The other three, boolean, string, and number all have wrapped versions, which are objects: Boolean, String, and Number. They are distinguished by starting with uppercase. This is the same sort of model used by Java: a hybrid of objects and primitives.

JavaScript will also box and unbox the primitives as needed.

In the following code, you can see the boxed ...

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