Building a Modern Mobile App Using Expo Go, News API, and MERN Stack with TypeScript Backend
As mobile app development evolves, developers seek to build smooth, fast, and scalable applications. A seamless user experience requires a robust front-end combined with a well-structured back-end. In this article, we explore how to build a mobile app using Expo Go for the front-end, fetching data from the News API, and leveraging the MERN Stack with TypeScript for the back-end. We’ll also discuss why the latest development techniques matter and share a code example to get you started.
Key Components:
- Expo Go for the front-end
- React Query for efficient data fetching
- TypeScript to build a robust back-end with MERN
- News API to populate the app with live data
By adopting these technologies, you’ll ensure your app is future-proof, highly responsive, and maintainable.
Step 1: Building the Front-End with Expo Go
Expo Go is an excellent choice for rapid mobile development. It allows you to build React Native apps faster without configuring a development environment from scratch. With features like hot reloading and cross-platform support, it simplifies the mobile app development process.
Here’s a breakdown of how the HomeScreen component fetches and displays news from the News API using React Query:
import React from 'react';
import { View, Text, ScrollView } from 'react-native';
import { useColorScheme } from 'nativewind';
import { useQuery } from '@tanstack/react-query';
import { fetchBreakingNews, fetchRecommendedNews } from '../../utils/NewsApiCall';
import { StatusBar } from 'expo-status-bar';
import Header from '../../components/Header';
import Loading from '../../components/Loading';
import MiniHeader from '../../components/MiniHeader';
import BreakingNews from '../../components/BreakingNews';
import { heightPercentageToDP as hp } from 'react-native-responsive-screen';
import NewsSection from '../../components/NewsSection';
import { SafeAreaView } from 'react-native-safe-area-context';
const HomeScreen = () => {
const { colorScheme } = useColorScheme();
const { data: breakingNewsData, isLoading: isBreakingNewsLoading, error: breakingNewsError } = useQuery({
queryKey: ["breakingNews"],
queryFn: fetchBreakingNews,
staleTime: 1000 * 60 * 5,
cacheTime: 1000 * 60 * 10,
});
const { data: recommendedNewsData, isLoading: isRecommendedNewsLoading, error: recommendedNewsError } = useQuery({
queryKey: ['recommendedNews'],
queryFn: fetchRecommendedNews,
staleTime: 1000 * 60 * 5,
cacheTime: 1000 * 60 * 10,
});
return (
{isBreakingNewsLoading ? (
) : breakingNewsError ? (
Error loading breaking news
) : (
)}
{isRecommendedNewsLoading ? (
) : recommendedNewsError ? (
Error loading recommended news
) : (
)}
);
};
export default HomeScreen;
In this example:
Expo Go serves as the foundation of the front-end.
React Query handles data fetching, caching, and background updating, making it easy to manage API calls and efficiently display breaking and recommended news.
The News API provides real-time data, which is displayed using components like BreakingNews and NewsSection.
Step 2: Building the Backend with TypeScript on MERN Stack
To complement the front-end, the back-end must be reliable and scalable. For this, we use the MERN Stack (MongoDB, Express.js, React, Node.js) with TypeScript to build a clean, type-safe back-end.
Why TypeScript?
TypeScript enhances JavaScript with strong typing, making your code more predictable and maintainable. Using TypeScript in your back-end will:
- Improve code quality with early error detection.
- Ensure type safety, reducing bugs in production.
- Enhance collaboration by providing clear interfaces and types.
Setting Up a TypeScript-Enabled Backend
Initialize the project: Start by creating a new Node.js project and initializing TypeScript:
mkdir mern-backend
cd mern-backend
npm init -y
npm install typescript @types/node @types/express express mongoose
Setup TypeScript Configuration: Add a tsconfig.json file to set up TypeScript:
{
"compilerOptions": {
"target": "ES6",
"module": "commonjs",
"strict": true,
"esModuleInterop": true,
"skipLibCheck": true,
"forceConsistentCasingInFileNames": true,
"outDir": "./dist"
},
"include": ["src/**/*"]
}
Create Express App with TypeScript: Now, let's create a simple Express server with TypeScript.
import express, { Request, Response } from 'express';
import mongoose from 'mongoose';
const app = express();
const PORT = process.env.PORT || 5000;
app.use(express.json());
app.get('/', (req: Request, res: Response) => {
res.send('TypeScript and Express are working together!');
});
mongoose.connect('your_mongo_db_connection_string')
.then(() => {
app.listen(PORT, () => {
console.log('Server running on port', PORT);
});
})
.catch((err) => {
console.error('MongoDB connection error:', err);
});
Build REST APIs: Using TypeScript, you can build REST APIs to handle the news data fetched from the News API or any custom back-end logic you need for the mobile app. Each endpoint will benefit from TypeScript’s type safety, making your code more robust and maintainable.
Run the App: Once the back-end is set up, you can compile TypeScript into JavaScript and run the app:
tsc
node dist/index.js
Step 3: Synchronizing the Front-End with the Back-End
The front-end developed with Expo Go can communicate with the TypeScript-powered back-end using REST APIs. Once the back-end is live, you can easily integrate it into the mobile app by changing the API call URLs in your Expo Go app to point to your own back-end rather than the News API.
Why Staying Updated with New Techniques Matters
Using up-to-date tools and frameworks in mobile development is crucial. It ensures:
Code Quality: Modern libraries and techniques prevent bad code practices and make your app easier to maintain and scale.
Performance: With updated dependencies, your app is optimized for the latest devices and platforms.
Security: Outdated dependencies can introduce security risks. Staying current reduces vulnerabilities.
Conclusion
Building a mobile app using Expo Go and News API for the front-end and a TypeScript-powered MERN stack for the back-end provides a well-rounded, scalable solution for modern app development. By leveraging the latest development techniques, you not only ensure smooth performance but also stay ahead of the curve with clean, maintainable code.
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