Understanding Objects in JavaScript

In our previous post, we learned that Arrays are great for lists. But what if you want to describe a specific person? Using an array like ["InsideTech", 21, " Engineering"] is confusing. Does "21" mean age, or is it a roll number?

Objects solve this by using a Key-Value Pair structure. Instead of just storing data, we give every piece of data a label (a key).

Topics we are going to cover in this blog are as follows

• Creating objects

• Accessing properties (dot notation and bracket notation)

• Updating object properties

• Adding and deleting properties

• Looping through object keys

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What is an Object?

An object is a collection of related data and/or functionality. It is the closest thing in code to a real-world entity.

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Creating an Object

We use curly braces {} to define an object literal.

const user = {
  name: "InsideTech",
  age: 21,
  city: "Ahmedabad",
  isStudent: true
};

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Accessing Properties

There are two ways to get data out of an object:

• Dot Notation (.): This is the most common and readable method.

  • console.log(user.name); // "InsideTech"

• Bracket Notation ([]): Essential if your key name is stored in a variable or has spaces.

  • console.log(user["city"]); // "Ahmedabad"

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Updating, Adding, and Deleting

Objects are dynamic. You can modify them even after they are created.

// 1. Updating
user.age = 20;

// 2. Adding a new property
user.hobby = "3D Modeling";

// 3. Deleting a property
delete user.isStudent;

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Understand through the below Table diagram

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Looping Through Objects

Unlike arrays, you can't use a standard for loop with an index. Instead, we use the for...in loop to iterate through the keys.

for (let key in user) {
  console.log(key + ": " + user[key]);
}
// Output: name: InsideTech, age: 20, city: Ahmedabad, hobby: 3D Modeling

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Conclusion

Objects are the "containers" of the JavaScript world. By mastering them, you can now structure complex data efficiently. This is a massive step you've moved from writing simple scripts to managing data structures that modern apps are built on.