effect-io-ai

Package: effect
Module: SchemaTransformation

SchemaTransformation.optionFromOptionalKey

Decodes an optional struct key into Option<T> and encodes Option<T> back to an optional key.

When to use

Use when you need a schema transformation to convert optional struct keys (declared with Schema.optionalKey) to Option values.

Details

Decoding maps an absent key (None) to Some(None) and a present key (Some(v)) to Some(Some(v)). Encoding maps Some(None) to None to omit the key, and maps Some(Some(v)) to Some(v). This uses transformOptional under the hood.

Example (Converting an optional key to an Option)

import { Schema, SchemaTransformation } from "effect"

const schema = Schema.Struct({
  name: Schema.optionalKey(Schema.String).pipe(
    Schema.decodeTo(
      Schema.Option(Schema.String),
      SchemaTransformation.optionFromOptionalKey()
    )
  )
})

See

• optionFromOptional
• optionFromUndefinedOr
• transformOptional

Signature

declare const optionFromOptionalKey: <T>() => Transformation<Option.Option<T>, T>

Source

Since v4.0.0