effect-io-ai

Package: effect
Module: Config

Config.withDefault

Provides a fallback value when the config fails due to missing data.

When to use

Use when you need to make a config key optional with a sensible default.

Gotchas

Only applies when the error is a SchemaError caused exclusively by missing data (missing keys, undefined values). Validation errors (wrong type, out of range) still propagate.

Example (Defaulting a missing port)

import { Config, ConfigProvider, Effect } from "effect"

const port = Config.number("port").pipe(Config.withDefault(3000))

const provider = ConfigProvider.fromUnknown({})
// Effect.runSync(port.parse(provider)) // 3000

See

• option – returns Option instead of a default value
• orElse – catches all errors, not just missing data

Signature

declare const withDefault: { <const A2>(defaultValue: A2): <A>(self: Config<A>) => Config<A2 | A>; <A, const A2>(self: Config<A>, defaultValue: A2): Config<A | A2>; }

Source

Since v2.0.0