Understanding Objects in JavaScript

I’ve been diving deep into JavaScript lately, and the best way to make sure I actually understand something is to write it down and explain it.

What Exactly is an Object?

The easiest way to think about an object is like a dictionary or the contacts app on your phone.

In a dictionary, you look up a word (the key), and it gives you the definition (the value). A JavaScript object is just a collection of these key value pairs. The key is the label, and the value is the data.

Creating an Object

const person = {
  name: "Raj",
  age: 28,
  city: "Jaipur"
};

How to Access the Data

Once your data is inside an object, you need to know how to get it out. I learned there are two ways to do this.

1. Dot Notation

console.log(person.name); 
console.log(person.city);

2. Bracket Notation

console.log(person["name"]); 

const whatIWantToKnow = "age";

console.log(person.whatIWantToKnow); // Output: undefined

console.log(person[whatIWantToKnow]); // Output: 28

Changing the Data

Modifying an object is pretty straightforward.

1. **Updating a Property -**Just grab the property and give it a new value.

person.age = 29; 

1. Adding a Property - You don't need to change the original object. Just pretend the new key already exists and assign something to it.

person.job = "Developer";

1. Deleting a Property - If you need to completely remove something, use the delete keyword.

delete person.city;

Looping Through an Object

what if you want to print out everything inside the object? Because objects don't have numbered indexes like arrays do, a normal for loop doesn't work.

const person = {
  name: "Raj",
  age: 28,
  city: "Jaipur"
};

for (let key in person) {
  // Notice I have to use bracket notation here because 'key' is a variable!
  console.log(`\({key} : \){person[key]}`);
}

/* Console Output:
name: Raj
age: 28
city: Jaipur
*/

That’s it for the basics, switching my mindset from putting everything in an array to using an object to label my data has made my code so much easier to read.