openapi-typescript-types

A library for generating Typescript types from an OpenAPI document.

Usage

The script can either be run through the command line or with a config file.

Config File

The preferred way of running ott is by using a config file. If the config file is named ott.config.yaml and stored in the current working directory, the script can be invoked with that config file by running:

ott --config ./ott.config.yaml

Config File Structure

The structure and options for the config file are defined below:

version: 1.0               # The config version, only supports 1.0
input: ./swagger.yaml      # The path to teh swagger file input
output: ./out/types.ts     # The output file for the typescript types

options:                   # Additional options (optional)
  typeNameFormat: "{name}" # Format the name of output types.
  
  paths:                   # Options for paths, paths excluded if false
    include:               # List specific paths to include.
      - /pet/**            #   - Takes precedence over "exclude"
      - /store/**
    exclude:               # List specific paths to exclude
      - /user/**           #   - Has no effect if "include" is specified
  
  schemas:                 # Options for schemas, all schemas excluded if false
    include:               # List specific paths to include.
      - Pet                #   - Takes precedence over "exclude"
      - Category
    exclude:               # List specific paths to exclude
      - Customer           #   - Has no effect if "include" is specified

Command Line

The script can also be run through the command line, although the options are more limited than the config file.

You can always run ott --help for the most detailed and up to date explanation of the command line options.

Command Line Example

Below is an example of invoking the command to generate a types file without schemas that will be named petstore-types.ts from an input file of petstore.yaml.

ott \
  --input petstore.yaml \
  --output petstore-types.ts \
  --exclude-schemas

Development

Prerequisites

Node version is pinned in .nvmrc (Node 24). If you use nvm:

nvm use

Setup

npm install

Scripts

• npm run build — Compile TypeScript sources to dist/ via tsc.
• npm run lint — Run ESLint over the repo (uses typescript-eslint's strict configs).
• npm run create-executable — Build and npm i -g so ott is available globally on your machine for end-to-end testing.
• npm test — Run the fixture-based test suite (see "Testing" below). Requires npm run build first.

Testing

The test suite (test/run.js) drives the built CLI against every fixture in test/fixtures/ and confirms the generated TypeScript compiles under tsc --strict. The default fixture (test/fixtures/test-api.yaml) covers the OpenAPI constructs ott supports: basic types, nullable types, enums, arrays (including nullable arrays of objects), nested objects, additionalProperties, oneOf/anyOf/allOf, path operations with request bodies and 2xx responses, and path variables.

npm run build
npm test

To extend coverage for a new construct or a regression, drop another *.yaml file into test/fixtures/ — the runner picks it up automatically. Generated output is written to test/output/ (gitignored).

CI workflows

Located in .github/workflows/:

• checks.yaml — Runs on every push to main and every pull request. Sets up Node from .nvmrc, runs npm ci, npm run lint, and npm run build. PRs must be green here before merge.
• pr-validate.yaml — Validates that the PR title follows Conventional Commits using amannn/action-semantic-pull-request. Only feat, fix, and chore prefixes are accepted.
• release.yaml — Runs on push to main. Uses release-please to open release PRs that bump the version and update CHANGELOG.md. Merging a release PR triggers a build and npm publish.

Release process

This repo uses release-please. Do not edit package.json's version field manually — release-please derives the next version from the Conventional Commit messages on main:

• feat: commits trigger a minor version bump.
• fix: commits trigger a patch version bump.
• feat!: (or any commit with a BREAKING CHANGE: footer) triggers a major version bump.
• chore: commits appear in the changelog under "Miscellaneous" and do not bump the version.

Sections in the generated changelog are configured in release-please-config.json.