Apply Types to Entire Function Expressions When Possible

Overview

Type entire functions at once instead of individual parameters.

When using function expressions (not statements), you can apply a type to the entire function. This reduces repetition, improves type safety, and makes code more readable.

When to Use This Skill

• Writing multiple functions with the same signature
• Implementing callbacks for libraries
• Matching signatures of existing functions
• Wrapping or extending existing functions

The Iron Rule