JavaScript – Object Basics By Satyen

8/7/2019 JavaScript Object Basics By Satyen

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By: Satyen Pandya

[email protected]@gmail.com

JavaScriptJavaScript Object BasicsObject Basics


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ContentsContents

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Object-Oriented Terminology

Early v/s. Late Binding

Types ofObjects

Defining Classes & Objects

Modifying Objects



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ObjectObject--Oriented TerminologyOriented Terminology

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ECMA-262 defines Object as an unordered collection of

properties each of which contains a primitive value,

object or function

Fourbasic features ofOOP:

1. Encapsulation

2. Aggregation

3. Inheritance

4. Polymorphism



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Early versus Late BindingEarly versus Late Binding

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Binding the method whereby an objects interface is

bound to an object instance

Early Binding Properties and methods are defined for

an object before it is instantiated

Late Binding The compiler/interpreter doesnt know

what type of object is being held until runtime

ECMAScript doesnt support early binding

ECMAScript uses late binding for all variables



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Types of ObjectsTypes of Objects

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Three types of objects can be used/created :

1. Native Objects

2. Built-in Objects

3. Host Objects



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Types of Objects (Contd)Types of Objects (Contd)

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Native Objects : any object supplied by an ECMAScript

implementation independent of the host environment

All the native objects includes a list ofbuilt-in functions

and properties

They includes :Array EvalError RangeError SyntaxError

Boolean Function ReferenceError TypeError

Date Number RegEcp URIError

Error Object String



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Built-in Objects : Object which is present at the start of

execution of ECMAScript program

It is already instantiated

ECMA-262 defines only two objects :

1. Global

2. Math Global includes functions like, isNan(), isFinite(), parseInt(),

parseFloat(), etc.

- properties like, undefined, NaN, Infinity, Constructors for

all Native Objects

Math includes functions like, max(), min(), ceil(), round(),

floor(), etc.

- properties like, E, LN10, LOG2E, LOG10E, PI, SQRT1_2,

SQRT2



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Host Objects : any object that is not a native

All BOM and DOM objects are host objects



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Defining Classes & ObjectsDefining Classes & Objects

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Classes can be defined same as function

We can define class in different ways :

1. Factory paradigm

2. Constructor paradigm

3. Prototype paradigm

4. Hybrid constructor/prototype paradigm

5. Dynamic prototype

6. Hybrid factory paradigm



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Modifying ObjectsModifying Objects

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Objects can be modified by using prototype property

We can modify object in different ways :

1. Creating a new method

2. Redefining an existing method

3. Very late binding



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Thank youThank you

By: Satyen Pandya


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JavaScript – Object Basics By Satyen