effect-facet-schema-decoding

name: effect-facet-schema-decoding description: Guidance for facet effect/Schema#decoding focused on APIs like decode, Decoder, and decodeTo. Load after effect-skill-router when this facet is the primary owner.

Effect Facet Schema#decoding

Owned scope

• Owns only effect/Schema#decoding.
• Parent module: effect/Schema.

What it is for

• decode and parse pathways. Module-specific APIs and usage patterns for Effect programs.

API quick reference

• decode
• Decoder
• decodeTo
• fromBrand
• decodeExit
• decodeSync
• decodeEffect
• decodeOption
• fromFormData
• decodePromise
• decodeUnknownEffect
• decodeUnknownExit
• decodeUnknownOption
• decodeUnknownPromise
• decodeUnknownSync
• fromJsonString
• fromURLSearchParams
• URLFromString
• Full API list: references/api-reference.md

How to use it

• Keep work focused on the decoding concern for effect/Schema.
• Start with constructor-style APIs to build values/services before composing operations.
• Use schema/codec APIs to validate inputs at boundaries before business logic.
• Keep runtime/execute APIs at edges; compose pure transformations before execution.

Starter example

import { Schema } from "effect"

// Define custom hook functions for error formatting
const leafHook = (issue: any) => {
  switch (issue._tag) {
    case "InvalidType":
      return "Expected different type"
    case "InvalidValue":
      return "Invalid value provided"
    case "MissingKey":
      return "Required property missing"
    case "UnexpectedKey":
      return "Unexpected property found"
    case "Forbidden":
      return "Operation not allowed"
    case "OneOf":
      return "Multiple valid options available"
    default:
      return "Validation error"
  }
}

// Create a standard schema from a regular schema
const PersonSchema = Schema.Struct({

Common pitfalls

• Prefer explicit, typed combinators over ad-hoc casting or unchecked assumptions.

Not covered here

• Sibling facets under the same parent are out of scope:
  • effect-facet-schema-checks (effect/Schema#checks)
  • effect-facet-schema-composition (effect/Schema#composition)
  • effect-facet-schema-core (effect/Schema#core)
  • effect-facet-schema-encoding (effect/Schema#encoding)
• Parent module ownership belongs to effect-module-schema.

Escalate to

• effect-module-schema for parent module-wide workflows.
• effect-skill-router for cross-module routing and ownership checks.

Reference anchors

• Parent tests: packages/effect/test/schema/Schema.test.ts
• Parent tests: packages/effect/test/JsonPatch.test.ts
• Parent tests: packages/effect/test/unstable/encoding/Sse.test.ts
• Parent tests: packages/effect/test/unstable/sql/SqlSchema.test.ts
• API details: references/api-reference.md
• Usage notes: references/usage-reference.md
• Ownership mapping: references/owner.md