📘️ swagger-to-io-ts

Convert Swagger files to io-ts types using Node.js. Based on swagger-to-ts.

💅 Prettifies output with Prettier.

To compare actual generated output, see the example folder.

Usage

CLI

npx swagger-to-io-ts schema.yaml --output schema.ts

# 🚀 schema.yaml -> schema.ts [2ms]

This will save a schema.ts file in the current folder. The CLI can accept YAML or JSON for the input file.

Generating multiple schemas

Say you have multiple schemas you need to parse. I’ve found the simplest way to do that is to use npm scripts. In your package.json, you can do something like the following:

"scripts": {
  "generate:specs": "npm run generate:specs:one && npm run generate:specs:two",
  "generate:specs:one": "npx swagger-to-io-ts one.yaml -o one.d.ts",
  "generate:specs:two": "npx swagger-to-io-ts two.yaml -o two.d.ts"
}

Rinse and repeat for more specs.

For anything more complicated, or for generating specs dynamically, you can also use the Node API (below).

CLI Options

Option	Alias	Default	Description
--wrapper	-w	declare namespace OpenAPI2	How should this export the types?
--output [location]	-o	(stdout)	Where should the output file be saved?
--swagger [version]	-s	2	Which Swagger version to use. Currently only supports 2.
--camelcase	-c	false	Convert snake_case properties to camelCase?

Node

npm i --save-dev swagger-to-io-ts

const { readFileSync } = require('fs');
const swaggerToIoTS = require('swagger-to-io-ts');

const input = JSON.parse(readFileSync('spec.json', 'utf8')); // Input can be any JS object (OpenAPI format)
const output = swaggerToIoTS(input); // Outputs TypeScript defs as a string (to be parsed, or written to a file)

The Node API is a bit more flexible: it will only take a JS object as input (OpenAPI format), and return a string of TS definitions. This lets you pull from any source (a Swagger server, local files, etc.), and similarly lets you parse, post-process, and save the output anywhere.

If your specs are in YAML, you’ll have to convert them to JS objects using a library such as js-yaml. If you’re batching large folders of specs, glob may also come in handy.

Node Options

Name	Type	Default	Description
wrapper	string	declare namespace OpenAPI2	How should this export the types?
swagger	number	2	Which Swagger version to use. Currently only supports 2.
camelcase	boolean	false	Convert snake_case properties to camelCase