Learn what 'declarative' truly means in the context of React. This post breaks down the concept with simple analogies and code examples, showing why it's a cornerstone of modern web development.

What Does “React is Declarative” Really Mean?

If you’ve just started learning React, you’ve probably heard this already:

“React is declarative.”

But what does that actually mean?

Let’s break it down in simple words with real-life examples, easy code, and zero jargon.

🧾 Imperative vs Declarative – What’s the Difference?

Think of it like this:

Imperative: You tell the computer how to do something, step by step.

Declarative: You tell the computer what you want, and let it figure out the “how.”

🍽️ Real-Life Example

You go to a restaurant.

Imperative: “I’ll walk to that empty table, pull the chair out, and sit down.”

Declarative: “Table for two, please.”

With the declarative way, you just say what you want and the staff handles the rest.

🗺️ One More Example

Your friend asks: “How do I reach your house from Walmart?”

Imperative: You list every turn and traffic light.

Declarative: You just give your address.

In both examples, the declarative way is simpler, cleaner, and doesn’t overwhelm the person (or the computer) with unnecessary steps.

👨‍💻 Now, Let’s Talk Code

🧑‍🏫 Imperative JavaScript:

function double(arr) {
  let result = [];
  for (let i = 0; i < arr.length; i++) {
    result.push(arr[i] * 2);
  }
  return result;
}

You’re telling the computer how to do each step: loop, multiply, push.

✅ Declarative JavaScript:

function double(arr) {
  return arr.map(item => item * 2);
}

Here, you’re just saying what you want: “double everything in this array.”

Same result, but way simpler.

⚛️ React is Declarative

In React, you don’t tell the browser exactly how to update the UI.

You just describe what the UI should look like based on the current state, and React handles the rest.

Example:

function Greeting({ name }) {
  return <h1>Hello, {name}!</h1>;
}

You’re not telling React how to render the <h1>, where to place it, or how to update it you’re just saying what it should show.

🤯 Bonus: Reusable & Readable

Declarative code is easier to:

Read
Maintain
Reuse in other projects

Since you’re focusing on what should happen, not how, your code can work in different places without breaking.

🎯 Key Takeaways

Imperative = manual, step-by-step.
Declarative = describe the goal, not the steps.
React is declarative because it lets you describe UI based on state.
Declarative code is usually easier to read and reuse.

Chapter 2 - What Does "React is Declarative" Really Mean?