Slow TypeScript compilation may stem from excessive type-checking or complex dependencies. Use incremental builds, project references, and `skipLibCheck` to improve speed.

Slow compilation times in TypeScript projects often occur due to extensive type-checking, especially in larger codebases or when multiple dependencies are interdependent. To address this, enable incremental builds by setting incremental: true in your tsconfig.json. This instructs TypeScript to reuse information from previous compilations, reducing the need to recompile unchanged files. Additionally, use project references to divide your code into smaller, manageable sections; each can be compiled independently, cutting down build times significantly. The skipLibCheck: true option can be a quick performance gain as well, as it bypasses type-checking for libraries, which usually don’t need re-validation. Tools like tsc-watch can help identify which files are taking longer to compile, allowing you to focus optimization efforts on problematic areas. Also, reducing the use of global types and preferring explicit types in function parameters can decrease compilation load. By implementing these strategies, you can achieve faster, more efficient TypeScript compilation, boosting developer productivity.