What is a JavaScript object?
In JavaScript, an object is a special reference type that contains key-value pairs. Objects allow us to store and organize data in a structured way.
Characteristics of objects:
- Key-value pairs: Objects contain key-value pairs, where the key is a unique identifier, and The value can be any JavaScript value (including another object).
- Reference type: Object is a reference type, which means that when we copy or pass an object, we actually copy or pass a reference to the object.
- Extensibility: Objects can dynamically add or delete attributes, allowing us to process data flexibly.
-
Indexable: The properties of an object can be accessed using square bracket syntax, such as
object["property"]
.
Creating objects:
There are two main ways to create objects:
-
Object literal : Use curly braces
{}
to create objects, for example:const person = { name: "John Doe", age: 30, occupation: "Software Engineer" };
-
Constructor: Use
new
Keywords and constructors to create objects, for example:function Person(name, age, occupation) { this.name = name; this.age = age; this.occupation = occupation; } const person = new Person("John Doe", 30, "Software Engineer");
Use objects:
We can use dot syntax or square bracket syntax to Access the properties of the object, for example:
-
Dot syntax:
object.property
-
Square bracket syntax:
object["property"]
We can also use the following methods to handle objects:
-
Add properties:
object.newProperty = value
-
Delete property:
delete object.property
-
Get property value:
object.property
orobject["property"]
-
Loop through objects:
for (const property in object)
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