JavaScript objects are fundamental data structures in the language, used to store collections of key-value pairs. They are versatile and can represent complex data in a structured way.
The Number Object
- The
Numberobject in JavaScript is a global object that represents numerical values. It’s one of the seven built-in data types in JavaScript and can represent both integer and floating-point numbers.
1. Creating Number Objects:
- You can create a
Numberobject using theNumber()constructor function:
const num = new Number(42);
Or you can simply use the primitive number literals:
const num = 42;
2. Properties of Number Object:
Number.MAX_VALUE: Returns the largest representable number in JavaScript.Number.MIN_VALUE: Returns the smallest positive representable number in JavaScript.Number.NaN: Represents “Not-A-Number” value.Number.NEGATIVE_INFINITY: Represents negative infinity.Number.POSITIVE_INFINITY: Represents positive infinity.
Object Literal:
An object literal is a comma-separated list of name-value pairs wrapped in curly braces {}. It’s a convenient way to create a single instance of an object.
const person = {
name: "John",
age: 30,
city: "New York"
};
Object Constructor:
JavaScript provides a built-in constructor function Object() to create objects.
const car = new Object();
car.make = "Toyota";
car.model = "Camry";
Properties:
Objects can have properties, which are essentially key-value pairs. Properties can be primitive data types like strings, numbers, or booleans, as well as objects or functions.
console.log(person.name); // Accessing property
using dot notation
console.log(car["make"]); // Accessing property
using bracket notation
Methods:
Properties can also hold functions, which are referred to as methods.
const calculator = {
add: function(x, y) {
return x + y;
},
subtract: function(x, y) {
return x - y;
}
};
console.log(calculator.add(5, 3));
// Outputs: 8
The this Keyword
- In a function definition,
thisrefers to the “owner” of the function. In the example above,
thisis the person object that “owns” thefullNamefunction.In other words,
this.firstNamemeans thefirstNameproperty of this object.
