react-from-zero

A Country Explorer app built with React + REST Countries API — from scratch, one step at a time.

Browse 250+ countries, search by name, filter by region, and view detailed info including borders, currencies, and languages. All data comes from the free REST Countries API — no API key needed.

Part of the TechFromZero series: learn a new technology every day by building a real project.

Live Demo: react-from-zero-mu.vercel.app

Quick Start

git clone https://github.com/dev48v/react-from-zero.git
cd react-from-zero
npm install
npm start

Opens at http://localhost:3000

Features

• Browse all 250+ countries with flags
• Search countries by name (instant filtering)
• Filter by region (Africa, Americas, Asia, Europe, Oceania)
• Click a country → detailed view with population, currencies, languages
• Click border countries → navigate between neighbors
• Responsive grid layout (auto-adjusts columns)
• Sticky header, smooth animations

API

Uses REST Countries API — completely free, no API key required.

Endpoint	Description
/all?fields=...	All countries (filtered fields for smaller response)
/alpha/{code}	Single country by 3-letter code
/region/{region}	Countries by region
/name/{name}	Search by name

Architecture

App (Router)
├── Header (sticky, clickable → home)
├── CountryList (home page)
│   ├── SearchBar (controlled input → filters by name)
│   ├── RegionFilter (dropdown → filters by continent)
│   └── CountryCard[] (grid of cards)
└── CountryDetail (detail page)
    └── Border buttons → navigate to neighbor countries

src/
├── App.js                  ← Root component + React Router
├── components/
│   ├── CountryCard.js      ← Single country card (flag + info)
│   ├── CountryList.js      ← Grid of cards + search + filter
│   ├── SearchBar.js        ← Search input (controlled component)
│   └── RegionFilter.js     ← Region dropdown
├── pages/
│   └── CountryDetail.js    ← Full country detail with borders
└── services/
    └── countryApi.js       ← REST Countries API client

Step-by-Step Commits

Each commit builds on the previous one:

1. Project setup — React app with header and folder structure
2. API client — REST Countries fetch helpers with field filtering
3. CountryCard — Reusable card component with flag, name, and info
4. CountryList — Responsive grid layout with API data fetching
5. SearchBar — Live filtering countries by name as you type
6. RegionFilter — Dropdown to filter countries by continent
7. CountryDetail — Detail page with routing, borders, and back navigation
8. Styling — Sticky header, fade-in animations, clickable title
9. README — This file

Key React Concepts Covered

1. Components — Breaking UI into reusable pieces (CountryCard, SearchBar)
2. Props — Passing data from parent to child
3. useState — Managing component state (countries, search text, loading)
4. useEffect — Fetching data on component mount
5. Lifting state up — Search/filter state lives in CountryList, passed down to inputs
6. Conditional rendering — Loading/error/empty states
7. React Router — URL-based navigation between pages
8. useParams — Extracting URL parameters
9. useNavigate — Programmatic navigation
10. CSS Grid — Responsive layout without media queries

Tech Stack

• React 18 — UI library
• React Router — Client-side routing
• REST Countries API — Free country data (no key needed)
• CSS — Custom styles (no UI framework)