fp-errors

# Practical Error Handling with fp-ts This skill teaches you how to handle errors without try/catch spaghetti. No academic jargon - just practical patterns for real problems. The core idea: **Errors are just data**. Instead of throwing them into the void and hoping someone catches them, return them as values that TypeScript can track. ## When to Use - You need to replace exception-heavy code with `Either` or `TaskEither`. - The task involves validation, domain errors, or clearer error contracts in TypeScript. - You want pragmatic fp-ts error-handling guidance for real application code. --- ## 1. Stop Throwing Everywhere ### The Problem with Exceptions Exceptions are invisible in your types. They break the contract between functions. ```typescript // What this function signature promises: function getUser(id: string): User // What it actually does: function getUser(id: string): User { if (!id) throw new Error('ID required') const user = db.find(id) if (!user) throw new Error('User not found') return user } // The caller has no idea this can fail const user = getUser(id) // Might explode! ``` You end up with code like this: ```typescript // MESSY: try/catch everywhere function processOrder(orderId: string) { let order try { order = getOrder(orderId) } catch (e) { console.error('Failed to get order') return null } let user try { user = getUser(order.userId) } catch (e) { console.error('Failed to get user') return null ...