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JavaScript vs TypeScript

Comparing JavaScript Source File and TypeScript Source File — which format should you use?

JavaScriptTypeScript
Full NameJavaScript Source FileTypeScript Source File
Extension.js.ts
MIME Typeapplication/javascriptapplication/typescript
Categorydatadata

JavaScript Pros

  • +Runs in every web browser
  • +Huge ecosystem (npm has 2M+ packages)
  • +Can be used for frontend and backend
  • +Dynamic and flexible

JavaScript Cons

  • -Dynamic typing can cause bugs
  • -Browser inconsistencies
  • -Security risks if not handled properly
  • -Can be slow for CPU-intensive tasks

TypeScript Pros

  • +Catches errors at compile time
  • +Better IDE support (autocomplete, refactoring)
  • +Makes large codebases manageable
  • +100% compatible with JavaScript

TypeScript Cons

  • -Requires compilation step
  • -Learning curve for type system
  • -Can add verbosity
  • -Build configuration complexity

Use JavaScript when...

  • -Web application frontend code
  • -Node.js server-side applications
  • -Browser extensions
  • -Mobile apps (React Native)
  • -Automation scripts

Use TypeScript when...

  • -Large-scale web applications
  • -API development
  • -React/Angular/Vue applications
  • -Library and framework development