Javascript Objects

A JavaScript object is a collection of properties, and a property is an association between a name and a value. A property’s value can be a function, in which case the property is known as a method.

Except number, string, boolean and undefined, everything in Javascript is object.

When an object is set to a variable, the variable is called reference type variable since it includes the reference (address) value of the object.

1. Object creation

1) Using object literal

2) using object creator (new Object())

3) using object constructor

2. Object property access/update

1) using [] or .

2) using for statement

3. Object/object property delete

The delete operator removes a property from an object.

The delete operator has no effect on regular variables, only properties of an object.

Since Javascript is garbage collected, you don’t need to delete objects themselves – they will be removed when there is no way to refer to them anymore.

4. Object references

1) Two variables share one object

Object Reference

2) Object comparison

Object Comparison

3) Always “Call by value”

Call by Value

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