> ## Documentation Index > Fetch the complete documentation index at: https://docs.cbrock.dev/llms.txt > Use this file to discover all available pages before exploring further. # Introduction > What ts-chas is and why you'd use it. `ts-chas` is a functional programming and utility library for TypeScript. It gives you a tightly integrated set of tools for writing code that is explicit about errors, safe at runtime, and easy to reason about without requiring a complete architectural overhaul of your project. ## Why ts-chas? TypeScript gives you compile-time safety, but several common patterns still leave you exposed at runtime: * **`try/catch`** makes errors untyped (`unknown`) and control flow implicit * **`null` and `undefined` checks** are easy to forget and don't compose * **Raw Promises** have no built-in retry, timeout, or cancellation * **Runtime validation** is often bolted on separately from the rest of your types * **Dummy data generation** often isn't exhaustive enough to fit to your constraints `ts-chas` addresses all of these with a single cohesive library. ## The modules Replace `try/catch` with `Result` (error types live in the function signature, not in your head). Chainable runtime validators that are also TypeScript type predicates. Use them inline or as schemas. Lazy async pipelines with retries, timeouts, circuit breakers, and caching built in. Discriminated error unions that let you match errors exhaustively, just like you match on data. Model optional values explicitly. `Option` shares the entire `Result` API. Compose small, focused functions into readable pipelines with full type inference. ## How the modules fit together What makes `ts-chas` different from a collection of unrelated utilities is that all modules are designed to interoperate: * A `Guard` can produce a `Result` directly via `.parse()` * An `Option` can be converted to a `Task` via `Task.fromOption()` * A `Result` can be converted to an `Option` via `.toOption()` * `Task` always resolves to a `ResultAsync` * `Tagged Errors` work with `.catchTag()` on `Result`, `ResultAsync`, and `Task` See [Cross-Module Patterns](/recipes/cross-module) for worked examples. ## Just try it, broh. Install ts-chas and set up your imports. A practical walkthrough with copy-paste examples.