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Programming Jan 11, 2026 · 12 min read

TypeScript Best Practices for Large Projects

Daniel

Software Developer

TypeScript has become the industry standard for large-scale JavaScript applications. However, as projects grow, maintaining type safety and build performance becomes challenging. Here are essential best practices for 2025.

1. Strict Type Checking

Always enable strict: true in your tsconfig.json. This turns on a family of strict type checking options that guarantee more type safety.

2. Use ‘unknown’ instead of ‘any’

The any type essentially disables type checking. Use unknown when you don’t know the type of a value, as it forces you to perform type checks before using it.

3. Utility Types

Master built-in utility types like Partial, Pick, Omit, and ReturnType. They help you perform type transformations without code duplication.

4. Project References

For very large monorepos, use Project References to split your codebase into smaller, independently compilable chunks. This significantly improves build times and IDE performance.

5. Zod for Runtime Validation

TypeScript only checks types at compile time. Use libraries like Zod to validate data at runtime, especially for API responses and form inputs.

Conclusion

Adopt these practices early to prevent technical debt and ensure your TypeScript codebase remains scalable and maintainable.