Optimizing TypeScript Compiler Settings for Faster Build Times

When working on TypeScript projects, slow build times can hinder productivity and cause frustration. Fortunately, optimizing your TypeScript compiler settings can significantly speed up build times. This article introduces simple, beginner-friendly changes you can make in your tsconfig.json file to improve compilation speed while still maintaining good error checking.

The TypeScript compiler uses a configuration file called tsconfig.json to understand how to compile your code. By customizing this file, you can control features that affect build speed. Let's explore some practical settings together.

1. Use Incremental Compilation Incremental compilation allows TypeScript to reuse information from previous compilations, reducing the amount of work needed with each build.

{
  "compilerOptions": {
    "incremental": true,
    "tsBuildInfoFile": "./buildcache/.tsbuildinfo"
  }
}

The "incremental" option must be set to true. Optionally, you can specify "tsBuildInfoFile" to control where the build cache file is saved. This speeds up builds especially when you don't modify many files.

2. Enable Skip Lib Check If you are confident about your dependencies (node_modules), you can skip type checking their declaration files to save time.

{
  "compilerOptions": {
    "skipLibCheck": true
  }
}

This option can greatly reduce build time by not checking all type declarations in your external libraries.

3. Use Isolated Modules for Faster Builds with Babel or ts-node If you're using a tool like Babel or ts-node that compiles TypeScript files individually, enabling "isolatedModules" can speed things up.

{
  "compilerOptions": {
    "isolatedModules": true
  }
}

Be aware that this flag disables some type checking features (like const enums), but it helps with faster incremental builds.

4. Restrict Your Files and Exclude Unnecessary Ones Configure the "include" and "exclude" arrays in tsconfig.json to only compile the files you need.

{
  "include": ["src/**/*"],
  "exclude": ["node_modules", "dist", "build"]
}

By excluding large folders or test files not needed during build, you can reduce compilation workload.

5. Use Module Resolution Strategies If your project structure is simple, set module resolution to "node" instead of "classic" for faster lookup.

{
  "compilerOptions": {
    "moduleResolution": "node"
  }
}

To wrap up, small changes in your TypeScript configuration can make a big difference. Start by enabling incremental builds and skipLibCheck. Then, refine includes and module resolution.

Remember to test your builds after changing any settings to ensure your code still compiles correctly without errors.

Happy coding, and enjoy your faster TypeScript builds!