JavaScript Enlightenment

دوره آموزش Javascript

1. JavaScript Objects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Creating Objects 1
JavaScript Constructors Construct and Return Object Instances 6
The JavaScript Native/Built-In Object Constructors 8
User-Defined/Non-Native Object Constructor Functions 9
Instantiating Constructors Using the new Operator 10
Creating Shorthand/Literal Values from Constructors 12
Primitive (a.k.a. Simple) Values 13
The Primitive Values null, undefined, “string”, 10, true, and false Are Not
Objects 15
How Primitive Values Are Stored/Copied in JavaScript 16
Primitive Values Are Equal by Value 17
The String, Number, and Boolean Primitive Values Act Like Objects When
Used Like Objects 18
Complex (a.k.a. Composite) Values 19
How Complex Values Are Stored/Copied in JavaScript 20
Complex Objects Are Equal by Reference 21
Complex Objects Have Dynamic Properties 22
The typeof Operator Used on Primitive and Complex Values 22
Dynamic Properties Allow for Mutable Objects 23
All Constructor Instances Have Constructor Properties that Point to Their
Constructor Function 24
Verify that an Object Is an Instance of a Particular Constructor Function 26
An Instance Created From a Constructor Can Have Its Own Independent
Properties (Instance Properties) 27
The Semantics of “JavaScript Objects” and “Object() Objects” 29
2. Working with Objects and Properties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Complex Objects Can Contain Most of the JavaScript Values as Properties 31
Encapsulating Complex Objects in a Programmatically Beneficial Way 32
Getting/Setting/Updating an Object’s Properties Using Dot Notation or
Bracket Notation 33
Deleting Object Properties 36
How References to Object Properties Are Resolved 36
Using hasOwnProperty, Verify That an Object Property Is Not From the
Prototype Chain 39
Checking If an Object Contains a Given Property Using the in Operator 39
Enumerate (Loop Over) an Object’s Properties using the for in Loop 40
Host Objects versus Native Objects 41
Enhancing and Extending Objects with Underscore.js 43
3. Object(). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Conceptual Overview of Using Object() Objects 45
Object() Parameters 46
Object() Properties and Methods 47
Object() Object Instance Properties and Methods 47
Creating Object() Objects Using “Object Literals” 48
All Objects Inherit From Object.prototype 49
4. Function(). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Conceptual Overview of Using Function() Objects 51
Function() Parameters 52
Function() Properties and Methods 53
Function Object Instance Properties and Methods 53
Functions Always Return a Value 53
Functions Are First-Class Citizens (Not Just Syntax but Values) 54
Passing Parameters to a Function 55
this and arguments Values Available To All Functions 55
The arguments.callee Property 56
The Function Instance length Property and arguments.length 57
Redefining Function Parameters 58
Return a Function Before It Is Done (Cancel Function Execution) 58
Defining a Function (Statement, Expression, or Constructor) 59
Invoking a Function [Function, Method, Constructor, or call() and apply()] 60
Anonymous Functions 61
Self-Invoking Function Expression 61
Self-Invoking Anonymous Function Statements 62
Functions Can Be Nested 62
Passing Functions to Functions and Returning Functions from Functions 63
Invoking Function Statements Before They Are Defined (Function Hoisting) 64