JavaScript Learning Notes: Objects

There are multiple ways to create objects in JavaScript. One way is by using the new Object() syntax, and another is by using the object literal syntax {}.

const tinderUser = new Object() 

                  const tinderUser = {}

                  tinderUser.id = "123abc"
                  tinderUser.name = "Sammy"
                  tinderUser.isLoggedIn = false

                  console.log(tinderUser);

Console Output:
{ id: '123abc', name: 'Sammy', isLoggedIn: false }


Nesting Objects

JavaScript allows you to nest objects within objects, which can be useful for organizing related data.


                const regularUser = {
                    email: "some@gmail.com",
                    fullname: {
                        userfullname: {
                            firstname: "hitesh",
                            lastname: "choudhary"
                        }
                    }
                }
                console.log(regularUser.fullname.userfullname.firstname);

Console Output:
hitesh 



                const obj1 = {1: "a", 2: "b"}
                const obj2 = {3: "a", 4: "b"}
                const obj3 = { obj1, obj2 }
                console.log(obj3);

Console Output:
{ obj1: { '1': 'a', '2': 'b' }, obj2: { '3': 'a', '4': 'b' } } 



                const obj1 = {1: "a", 2: "b"}
                const obj2 = {3: "a", 4: "b"}
                const obj4 = {5: "a", 6: "b"}
                const obj3 = Object.assign({}, obj1, obj2, obj4)
                console.log(obj3);

Console Output:
{ '1': 'a', '2': 'b', '3': 'a', '4': 'b', '5': 'a', '6': 'b' } 



                    const obj1 = {1: "a", 2: "b"}
                    const obj2 = {3: "a", 4: "b"}
                    const obj4 = {5: "a", 6: "b"}
                    const obj3 = {...obj1, ...obj2, ...obj4}
                    console.log(obj3);

Console Output:
{ '1': 'a', '2': 'b', '3': 'a', '4': 'b', '5': 'a', '6': 'b' }


  • JavaScript provides several built-in methods to work with objects, such as Object.keys(), Object.values(), and Object.entries().
    • 
                    const tinderUser = { id: '123abc', name: 'Sammy', isLoggedIn: false }
                    console.log(tinderUser);

                    console.log(Object.keys(tinderUser));
                    console.log(Object.values(tinderUser));
                    console.log(Object.entries(tinderUser));
                    console.log(tinderUser.hasOwnProperty('isLoggedIn'));

    Console Output:
    { id: '123abc', name: 'Sammy', isLoggedIn: false }
    [ 'id', 'name', 'isLoggedIn' ]
    [ '123abc', 'Sammy', false ]
    [ [ 'id', '123abc' ], [ 'name', 'Sammy' ], [ 'isLoggedIn', false ] ]
    true

    The hasOwnProperty() method is used to check if a specific property exists in an object.

    This method is useful for verifying the existence of properties before attempting to access them.


    Destructuring Objects

    Destructuring allows you to unpack properties from an object into distinct variables.

    
                    const course = {
                        coursename: "js in hindi",
                        price: "999",
                        courseInstructor: "hitesh"
                    };

                    const {courseInstructor: instructor} = course;
                    console.log(instructor);

    Console Output:
    hitesh

    Destructuring provides a clean syntax to extract and assign variables from objects.