When building modern web applications, we need a system that allows for scalability, maintainability, and reusability. This is where component architecture design comes in. Popular frontend libraries like React and Vue are built around this concept, enabling developers to break their UI into self-contained, reusable components.
In this post, we'll explore what component architecture is, why it's beneficial, and how to design a structured component-based project using React (or Next.js). To make it practical, let's consider a simple to-do list application.
What Is Component Architecture?
Component architecture is a way of designing an application where the UI is divided into smaller, independent pieces called components. Each component is responsible for rendering a piece of the interface and can manage its own state and behavior.
For example, in a to-do list application, different parts of the UI can be separated into components such as:
- TodoItem (displays an individual to-do task)
- TodoList (lists all tasks)
- AddTodoForm (allows users to add new tasks)
- FilterControls (lets users filter completed and pending tasks)
Each of these components can be developed, tested, and reused independently.
Benefits of Component-Based Design
1. Reusability
Instead of duplicating code, we can reuse components throughout the application. For instance, a Button component can be used for adding, deleting, or marking tasks as complete with minor styling adjustments.
2. Maintainability
Since components are modular, updating or fixing bugs in one area of the application doesn't impact other parts, making maintenance easier.
3. Scalability
As the application grows, new features can be added by simply creating new components or enhancing existing ones.
4. Separation of Concerns
Each component has a clear responsibility. The TodoItem component only renders a task, while the AddTodoForm component handles user input.
Structuring a To-Do Application with Components
Let's break down a simple component structure for our project:
/components
├── TodoItem.js
├── TodoList.js
├── AddTodoForm.js
├── FilterControls.js
├── Layout.js
/pages
├── index.js (Main application page)
In Next.js, which is a React framework, the /pages directory determines routing, while the /components directory houses reusable UI components.
Implementing Key Components
TodoItem Component (Displaying a Task)
import React from 'react';
const TodoItem = ({ task, onToggle }) => {
return (
<div className="border p-2 rounded flex justify-between">
<span className={task.completed ? "line-through" : ""}>{task.text}</span>
<button onClick={() => onToggle(task.id)}>
{task.completed ? "Undo" : "Complete"}
</button>
</div>
);
};
export default TodoItem;
TodoList Component (List of Tasks)
import React from 'react';
import TodoItem from './TodoItem';
const TodoList = ({ tasks, onToggle }) => {
return (
<div className="space-y-2">
{tasks.map((task) => (
<TodoItem key={task.id} task={task} onToggle={onToggle} />
))}
</div>
);
};
export default TodoList;
AddTodoForm Component (Adding New Tasks)
import React, { useState } from 'react';
const AddTodoForm = ({ onAdd }) => {
const [text, setText] = useState("");
const handleSubmit = (e) => {
e.preventDefault();
if (text.trim()) {
onAdd(text);
setText("");
}
};
return (
<form onSubmit={handleSubmit} className="flex space-x-2">
<input
type="text"
value={text}
onChange={(e) => setText(e.target.value)}
placeholder="Add a new task"
className="border p-2 rounded"
/>
<button type="submit" className="bg-blue-500 text-white px-4 py-2 rounded">
Add
</button>
</form>
);
};
export default AddTodoForm;
Composition: Bringing It All Together
In Next.js, we can create a homepage that puts these components together:
import { useState } from 'react';
import TodoList from '@/components/TodoList';
import AddTodoForm from '@/components/AddTodoForm';
export default function HomePage() {
const [tasks, setTasks] = useState([]);
const addTask = (text) => {
setTasks([...tasks, { id: Date.now(), text, completed: false }]);
};
const toggleTask = (id) => {
setTasks(tasks.map(task => task.id === id ? { ...task, completed: !task.completed } : task));
};
return (
<div className="container mx-auto p-4">
<AddTodoForm onAdd={addTask} />
<TodoList tasks={tasks} onToggle={toggleTask} />
</div>
);
}
Best Practices for Component Architecture
- Keep Components Small & Focused – Each component should have a single responsibility.
- Use Props for Data Flow – Components should receive data via props instead of depending on global state.
- Extract Reusable Logic – Use hooks like
useTodoData()for shared logic. - Organize Files Logically – Follow a structure that makes navigation easy.
- Optimise Performance – Use React.memo and lazy loading for better efficiency.
Conclusion
Component architecture is a game-changer in modern frontend development, making applications more maintainable, scalable, and efficient. By designing applications with a well-thought-out component structure, we can build rich, interactive user experiences without sacrificing code quality.
Whether you're building a to-do list app, a social media platform, or a complex dashboard, breaking it down into reusable components is the key to success. Happy coding!