The decision between TypeScript and JavaScript is one of the most debated in modern web development. Although TypeScript has gained massive popularity, JavaScript remains relevant and powerful for many use cases.
What is TypeScript?
TypeScript is a superset of JavaScript that adds optional static typing. Developed by Microsoft, it compiles to pure JavaScript and can run in any environment that supports JavaScript.
Advantages of TypeScript
1. Compile-time Error Detection
The TypeScript compiler detects errors before executing the code:
- Type errors (trying to use a string as a number)
- Non-existent properties on objects
- Missing or incorrect function parameters
- Unhandled null/undefined values
2. Better Developer Experience
IDEs can provide better support:
- Intelligent autocomplete based on types
- Safe refactoring
- Inline documentation with JSDoc
- Improved code navigation
3. Self-documenting Code
Types serve as documentation:
- Interfaces define clear contracts
- Return types document behavior
- Generics provide flexibility with safety
4. Maintainability in Large Projects
In extensive codebases, TypeScript shines:
- Safer refactorings
- Fewer errors in production
- Faster onboarding for new developers
- More predictable code
Advantages of JavaScript
1. Simplicity and Speed
JavaScript is more direct for small projects:
- No compiler configuration
- No types to write and maintain
- Faster development for MVPs
- Less cognitive overhead
2. Learning Curve
More accessible for beginners:
- Simpler syntax
- Fewer concepts to learn
- Immediate feedback without compilation
3. Flexibility
JavaScript allows for more dynamic patterns:
- Rapid prototyping
- Duck typing when useful
- Fewer structural restrictions
When to Use TypeScript
Large and Long-term Projects
If your project has or will have:
- More than 10,000 lines of code
- Multiple developers working simultaneously
- Years of lifespan
- Complex APIs with multiple integrations
Large Teams
TypeScript facilitates collaboration:
- Clear contracts between modules
- Less ambiguity in interfaces
- More effective code reviews
- Less time spent debugging
Critical Applications
Where bugs are costly:
- Financial applications
- Healthcare systems
- High-volume e-commerce
- Critical infrastructure
Public Libraries and Frameworks
If you develop code for others:
- Better experience for consumers
- Integrated type documentation
- Fewer reported issues
When to Use JavaScript
Small Scripts and Utilities
For simple tasks:
- Automation scripts
- Build utilities
- Small helpers
- Proofs of concept
Rapid Prototyping
When speed is crucial:
- Hackathons
- MVPs to validate ideas
- Client demos
- Technical experiments
Projects with Limited Resources
When time or expertise is scarce:
- Teams that don't know TypeScript
- Very tight deadlines
- Short-term projects
Highly Dynamic Code
Some patterns are more natural in JS:
- Extensive metaprogramming
- Very flexible configurations
- Dynamic plugins
Gradual Migration: The Best of Both Worlds
Incremental Adoption Strategy
It's not black or white, you can:
- Start with JavaScript and migrate module by module
- Use TypeScript only in critical parts
- Leverage JSDoc for types without a compiler
- Configure TypeScript in permissive mode initially
allowJs and checkJs
TypeScript can work alongside JavaScript:
- allowJs: Allows .js files in a TypeScript project
- checkJs: Verifies types in JavaScript files
- Gradual migration without rewriting everything
Performance Considerations
Compile Time
TypeScript adds a compilation step:
- Large projects can take minutes
- Affects development speed
- Mitigable with incremental compilation
- Watch mode improves the experience
Runtime Performance
TypeScript compiles to JavaScript, so:
- Same performance in production
- Types are completely removed
- Can generate more optimized code in some cases
Ecosystem and Tools
TypeScript has the advantage in:
- Modern frameworks (Angular requires TS)
- React with better experience
- Enterprise libraries (NestJS, TypeORM)
- Advanced development tooling
JavaScript remains king in:
- Simple Node.js scripts
- Configurations (webpack, babel)
- Some legacy frameworks
- Basic tutorials and documentation
Final Recommendations
Use TypeScript if:
- Your project will grow significantly
- You work in a team
- You value type safety
- You can invest in initial setup
Use JavaScript if:
- Small and self-contained project
- Rapid prototyping
- One-off scripts
- Team without TS experience
Conclusion
There is no single answer. TypeScript offers robustness and scalability at the cost of initial complexity. JavaScript offers simplicity and speed at the cost of type safety.
The industry trend is clear: TypeScript is gaining ground in professional projects. However, JavaScript remains perfect for scripts, prototyping, and small projects.
At Brixato, we evaluate each project individually. For enterprise applications, we almost always choose TypeScript. For internal utilities and scripts, JavaScript remains our choice.