Object in JavaScript
Objects in JavaScript
Objects in JavaScript are essential data structures that allow us to store collections of key-value pairs.
They serve as blueprints for organizing and managing data efficiently within our code.
Creating Objects
Objects are created using curly braces {} and consist of key-value pairs. Each key is a unique identifier associated with a value. For example:
let person = {
name: "Tom",
age: 27,
eyeColor: "blue",
updateAge: function () {
return ++this.age;
},
};Accessing Object Properties
Properties of an object can be accessed
using dot notation (object.property)
bracket notation (object['property']).
Example:
console.log(person.name); // Output: Tom
console.log(person["age"]); // Output: 27Manipulating Objects
Adding Properties:
Properties can be added to an object by simply assigning a value to a new key.
let person = {
name: "John",
age: 30,
};
// Adding a new property
person.city = "New York";
console.log(person); // Output: { name: 'John', age: 30, city: 'New York' }Removing Properties
Properties can be removed using the delete keyword.
let person = {
name: "John",
age: 30,
city: "New York",
};
// Removing a property
delete person.city;
console.log(person); // Output: { name: 'John', age: 30 }Object Methods
Objects can contain methods, which are functions stored as property values. These methods can perform operations on the object's data.
let calculator = {
number1: 0,
number2: 0,
// Method to add
add: function () {
return this.number1 + this.number2;
},
// Method to subtract
subtract: function () {
return this.number1 - this.number2;
},
};
// Setting operands
calculator.number1 = 10;
calculator.number2 = 5;
console.log(calculator.add()); // Output: 15
console.log(calculator.subtract()); // Output: 5Object Constructors
Object constructors allow us to create multiple instances of an object with similar properties and methods.
We define a blueprint for the object, and then create instances based on that blueprint.
Example:
function Person(name, age, eyeColor) {
this.name = name;
this.age = age;
this.eyeColor = eyeColor;
this.updateAge = function () {
return ++this.age;
};
}
let person1 = new Person("Tom", 27, "blue");
let person2 = new Person("Alice", 30, "green");Advantages of Object Constructors
Using object constructors helps in organizing data and reducing redundancy.
It allows for the creation of multiple instances of an object with ease, enabling efficient management of related data.
Ref
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