Managing Asynchronous Side Effects in PureScript with Aff

Problem and Takeaway

The core difficulty when building production‑grade PureScript applications is handling asynchronous operations—HTTP requests, timers, or any I/O—without sacrificing the language's guarantees of purity and stack safety. The useful takeaway is that the Aff monad, together with proper FFI wrapping and resource‑management patterns, provides a reliable, stack‑safe way to compose async effects while keeping error handling explicit.

Prerequisites

• A recent Node.js environment (v18+) with npm.
• PureScript 0.14+ (the current stable release) installed globally via npm install -g purescript.
• Spago (the PureScript build tool) initialized in a new project directory.
• Basic familiarity with PureScript syntax and the Effect monad for synchronous side effects.

All commands below assume you are in the project root and have npm install permissions.