effect-io-ai

Package: effect
Module: Effect

Effect.try

Creates an Effect that represents a synchronous computation that might fail.

When to Use

In situations where you need to perform synchronous operations that might fail, such as parsing JSON, you can use the try constructor. This constructor is designed to handle operations that could throw exceptions by capturing those exceptions and transforming them into manageable errors.

Error Handling

There are two ways to handle errors with try:

1. If you don’t provide a catch function, the error is caught and the effect fails with an UnknownException.
2. If you provide a catch function, the error is caught and the catch function maps it to an error of type E.

Example (Safe JSON Parsing)

import { Effect } from "effect"

const parse = (input: string) =>
  // This might throw an error if input is not valid JSON
  Effect.try(() => JSON.parse(input))

//      ┌─── Effect<any, UnknownException, never>
//      ▼
const program = parse("")

Example (Custom Error Handling)

import { Effect } from "effect"

const parse = (input: string) =>
  Effect.try({
    // JSON.parse may throw for bad input
    try: () => JSON.parse(input),
    // remap the error
    catch: (unknown) => new Error(`something went wrong ${unknown}`)
  })

//      ┌─── Effect<any, Error, never>
//      ▼
const program = parse("")

See

• sync if the effectful computation is synchronous and does not throw errors.

Signature

declare const try: { <A, E>(options: { readonly try: LazyArg<A>; readonly catch: (error: unknown) => E; }): Effect<A, E>; <A>(thunk: LazyArg<A>): Effect<A, Cause.UnknownException>; }

Source

Since v2.0.0