effect-io-ai

Package: effect
Module: Context

Context.getOption

Gets the service for a key safely wrapped in an Option.

When to use

Use when you need to read a Context service as an Option so absence is represented as data.

Details

Returns Option.some when the service is stored in the context. If the key is a Context.Reference and no override is stored, returns Option.some of the cached default value. Missing non-reference keys return Option.none.

Example (Getting optional services)

import { Context, Option } from "effect"
import * as assert from "node:assert"

const Port = Context.Service<{ PORT: number }>("Port")
const Timeout = Context.Service<{ TIMEOUT: number }>("Timeout")

const context = Context.make(Port, { PORT: 8080 })

assert.deepStrictEqual(
  Context.getOption(context, Port),
  Option.some({ PORT: 8080 })
)
assert.deepStrictEqual(Context.getOption(context, Timeout), Option.none())

See

• getOrElse for returning a fallback value directly

Signature

declare const getOption: { <S, I>(service: Key<I, S>): <Services>(self: Context<Services>) => Option.Option<S>; <Services, S, I>(self: Context<Services>, service: Key<I, S>): Option.Option<S>; }

Source

Since v2.0.0