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Object Fundamentals

Common JavaScript Types

Name Value
Undefined undefined
Null null
Boolean true
String "foo"
Number 3.14159
Object { bar: "baz" }
Function function qux() {...}
Array [ "hoge", 42 ]
RegExp /piyo/

Primitive Types

Name Value
Undefined undefined
Null null
Boolean true
String "foo"
Number 3.14159
Object { bar: "baz" }

Special Objects

Name Value
Function function qux() {...}
Array [ "hoge", 42 ]
RegExp /piyo/

Objects

An Object is a set of name/value pairs, also known as key/value pairs.

  • A key name must be in the form of a string.
  • Each string can be associated with any type (primitive type or object type)
    • Primitive types are passed by their value.
    • Object types are passed by their reference.

Functions

Functions are just regular kinds of objects. When a function is defined, it has three properties already defined:

  • name - The name of the function
  • length - The number of arguments
  • prototype - TBD

Methods

When you put a function inside of an object it’s typically called a method.

Post written on June 17, 2015
Post written on 2015-06-17 00:00:00 -0700