TypeScript utility types you’re probably underusing

TypeScript utility types are powerful tools for transforming, reusing, and refining existing types in a codebase, helping to prevent type drift and maintenance issues. Common utility types such as Partial, Pick, and Readonly are often used, but TypeScript offers more advanced types like ReturnType, Awaited, Parameters, and Extract, which preserve function signatures, unwrap promises, and manipulate discriminated unions. These types are especially useful in dynamic code sections like API clients, state machines, and plugin registries, where they help keep related types in sync with source code and maintain consistency. Utility types like Record and InstanceType enforce exhaustive key checks and maintain the relationship between class constructors and their instances, providing robust solutions for managing complex type hierarchies. While they enhance maintainability by reducing code duplication and preventing drift, they should be used judiciously, as they come with a readability cost. The key to effective use is ensuring these types eliminate secondary sources of truth, thereby facilitating easier refactoring and long-term code maintenance.