# Transformers Generator

> Design of the ejected Redocly `transformers` client generator. Read it, and update it, before changing generators/transformers/.

- Skill: `redocly/transformers-generator` (Agent Skill)
- Install (CLI): `npx skillmds@latest add redocly/transformers-generator`
- Raw SKILL.md: https://api.skillmd.com/api/skills/redocly/transformers-generator/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: redocly (https://skillmd.com/u/redocly)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/redocly/transformers-generator

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# The `transformers` generator — its skill

This file is the DESIGN of your ejected `transformers` generator (`generators/transformers/`):
**to change the generator, edit this skill first, then make the code match it** — a diff
to `generators/transformers/` that has no covering sentence here is incomplete.

## What it emits

Per-schema `to<Name>()` / `from<Name>()` converters that turn wire JSON into typed
values and back — the bridge for `dateType: Date` clients.

## Design decisions that must hold

- **Requires `dateType: Date`** (declared as `dateTypes: ['Date']`, so a mismatched
  selection fails fast): the converters assign `Date` objects to fields the sdk types as
  `Date`, which only type-checks in that mode.
- **Imports the sdk's schema TYPES** (so `typescript` is required) and nothing else.
- Converters are pure and total: every named schema gets a pair, nested structures
  recurse, and a missing optional stays missing.

## The stage files

`render.ts` holds the whole converter renderer; `index.ts` is the entry. Naming comes
from the TypeScript printer (`@redocly/client-generator/printers/typescript`).

## Ejecting it

`redocly eject-generator transformers` copies this generator's TypeScript source folder
to `generators/transformers/`, exactly as we wrote it, importing
`@redocly/client-generator` and `@redocly/client-generator/printers/typescript`. Running
a `.ts` generator uses Node's type stripping (Node 22.18, 23.6, or newer); newer built-in
versions merge in per file with `--update`. Change which fields are converted, or how,
and regenerate.

## The modify loop

1. Edit this skill: state the new behavior or decision.
2. Make `generators/transformers/` match it.
3. Run `redocly generate-client` and inspect the `git diff` of the generated output —
   generated files are never hand-edited.

Newer built-in versions merge in with `redocly eject-generator transformers --update`.