JavaScript Objects
Duration : 00:01:45
Objects:
Objects in JavaScript are data structures that store key-value pairs and represent entities with properties and methods.Example:
let car = { brand: "Toyota", model: "Camry" };
Dot Notation for Accessing Object Properties:
You can use dot notation to access properties of an object by directly referencing the property name after the object.Example:
let person = { name: "Alice", age: 25 };
console.log(person.name); // Output: Alice
Properties and Values of a JavaScript Object:
You can retrieve all properties or values of an object using 'Object.keys()' or 'Object.values()' respectively.Example:
let person = { name: "Eve", age: 28 };
let keys = Object.keys(person); // ['name', 'age']
let values = Object.values(person); // ['Eve', 28]
JavaScript Objects are Mutable:
Objects are mutable, meaning you can modify their properties after creation.Example:
let dog = { breed: "Labrador" };
dog.breed = "Golden Retriever"; // Mutable
JavaScript Passing Objects as Arguments:
Objects can be passed as arguments to functions, allowing you to modify their properties.Example:
function incrementAge(person) {
person.age += 1;
}
let person = { name: "David", age: 40 };
incrementAge(person); // 'person' age becomes 41
JavaScript Object Methods:
Objects can contain methods (functions) as properties.Example:
let calculator = {
add: function(a, b) {
return a + b;
}
};
console.log(calculator.add(3, 5)); // Output: 8
JavaScript Destructuring Assignment Shorthand Syntax:
Destructuring allows you to extract object properties into variables.Example:
let person = { name: "Frank", age: 28 };
let { name, age } = person; // Destructuring
Shorthand Property Name Syntax for Object Creation:
When creating objects, you can use shorthand notation if the variable names match the property names.Example:
let name = "Grace", age = 30;
let person = { name, age }; // Shorthand notation
The "this" Keyword:
In a method of an object, 'this' refers to the object itself.Example:
let car = {
brand: "Tesla",
info: function() {
return 'Brand: ${this.brand}';
}
};
console.log(car.info()); // Output: Brand: Tesla
JavaScript Function "this":
The value of 'this' in a regular function depends on how the function is called.Example:
function greet() {
console.log('Hello, ${this.name}');
}
let person = { name: "Helen" };
greet.call(person); // Output: Hello, Helen
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