fp-ts Skills

Apply practical functional TypeScript patterns with focused guides and quick references.

The complete fp-ts package covers composition, algebraic types, Option and Either, asynchronous effects, validation, transformations, immutable data, React, backend work, and refactoring.

Use cases

• Model nullable values and typed errors
• Compose asynchronous and validation pipelines
• Refactor React or backend TypeScript

How to use

Provide the existing code and desired behavior. Use a quick reference for a narrow question or a full pattern guide for design and refactoring; match the project’s fp-ts version.

Skills

• fp-ts Algebraic Data Types and Type Classes

  Product types, sum types, semigroups, monoids, Eq, Ord, and building custom type class instances for domain modeling in TypeScript

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• fp-ts-async-practical

  Practical async patterns using TaskEither - clean pipelines instead of try/catch hell, with real API examples

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• fp-ts-backend

  Functional programming patterns for Node.js/Deno backend development using fp-ts, ReaderTaskEither, and functional dependency injection

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• Function Composition - Building from Small Pieces

  Practical patterns for composing functions in TypeScript using pipe, flow, and functional design principles

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• Practical Data Transformations

  Everyday data transformations using functional patterns - arrays, objects, grouping, aggregation, and null-safe access

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• fp-ts Do Notation

  Master Do notation in fp-ts to write readable, sequential functional code without callback hell. Covers bind, apS, let, bindTo and real-world patterns.

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• Practical Error Handling with fp-ts

  Stop throwing everywhere - handle errors as values using Either and TaskEither for cleaner, more predictable code

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• Functional Programming Fundamentals

  Core FP concepts including pure functions, currying, composition, and pointfree style - the foundation for mastering functional TypeScript

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• fp-immutable

  Practical immutability patterns in TypeScript - spread operators, nested updates, readonly types, and when mutation is actually fine

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• fp-ts Option and Either

  Functional error handling and nullable value management using fp-ts Option and Either types

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• fp-ts Pipe and Flow Composition

  Master function composition in fp-ts using pipe and flow for building elegant, type-safe data transformation pipelines

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• Pragmatic Functional Programming

  A practical, jargon-free guide to functional programming - the 80/20 approach that gets results without the academic overhead

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• Functional Programming in React

  Practical patterns for using fp-ts with React - hooks, state, forms, data fetching. Works with React 18/19, Next.js 14/15.

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• fp-refactor

  Comprehensive guide for refactoring imperative TypeScript code to fp-ts functional patterns

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• Managing Side Effects Functionally

  Master functional approaches to side effects including IO types, effect isolation, idempotent operations, and quarantining impure code - essential patterns for reliable TypeScript applications

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• fp-ts-task-either

  Functional async patterns using TaskEither for type-safe error handling in TypeScript

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• fp-ts-validation

  Validation patterns using fp-ts with error accumulation, form validation, and API input validation

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• fp-either-ref

  Quick reference for Either type. Use when user needs error handling, validation, or operations that can fail with typed errors.

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• fp-option-ref

  Quick reference for Option type. Use when user needs to handle nullable values, optional data, or wants to avoid null checks.

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• fp-pipe-ref

  Quick reference for pipe and flow. Use when user needs to chain functions, compose operations, or build data pipelines in fp-ts.

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• fp-taskeither-ref

  Quick reference for TaskEither. Use when user needs async error handling, API calls, or Promise-based operations that can fail.

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• fp-types-ref

  Quick reference for fp-ts types. Use when user asks which type to use, needs Option/Either/Task decision help, or wants fp-ts imports.

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