Capacitor

Capacitor by Ionic is a cross-platform native runtime that makes it easy to build web apps that run on iOS, Android, and the web as Progressive Web Apps (PWAs). It provides a bridge to native APIs.

When to Use

• Converting existing React/Angular/Vue web apps to mobile apps.
• Need specific native functionality (Camera, Haptics, Push) in a web app.
• Building plugins that need to work across iOS, Android, and Web consistent APIs.

Quick Start

npm install @capacitor/core @capacitor/cli
npx cap init MyMobileApp com.example.app
npm install @capacitor/android @capacitor/ios
npx cap add android
npx cap add ios

import { Geolocation } from "@capacitor/geolocation";

const printCurrentPosition = async () => {
  const coordinates = await Geolocation.getCurrentPosition();
  console.log("Current position:", coordinates);
};

Core Concepts

Native Bridge

Capacitor injects a native bridge into the WebView, allowing JavaScript to call Native Code (Java/Kotlin/Swift/Obj-C) asynchronously.

Plugins

Modular blocks of code that provide interface to native functionality.

• Official Plugins: Maintained by Ionic team (Camera, Filesystem).
• Community Plugins: Maintained by the community.

Native Project Management

Capacitor treats native projects (android/, ios/) as “source artifacts”, meaning you commit them to git and use native tooling (Android Studio/Xcode) to build and configure them (permissions, icons).

Common Patterns

Secure Storage

Use @capacitor-community/http for secure requests (bypassing CORS) and secure storage plugins for tokens (Keychain/Keystore) instead of localStorage.

Deep Linking

Handle custom URL schemes (myapp://) for authentication redirects or opening specific content.

Best Practices

Do:

• Use official plugins whenever possible for long-term maintenance.
• Sync your project frequently: npx cap sync.
• Handle Permissions gracefully in your UI before calling native APIs.
• Use Live Reload during development: npx cap run android -l --external.

Don’t:

• Don’t store sensitive data (API Keys) in JS code; use environment variables or native config.
• Don’t ignore platform differences; test on real iOS and Android devices.
• Don’t rely on alert()/confirm(); use Capacitor Dialog plugin or UI framework modals.

Troubleshooting

References

• Capacitor Documentation
• Capacitor Plugins