msw-auto-mock

A cli tool to generate random mock data from OpenAPI descriptions for msw.

Why

We already have all the type definitions from OpenAPI spec so hand-writing every response resolver is completely unnecessary.

This tool also requires @faker-js/faker >= 7.

Install:

yarn add msw-auto-mock @faker-js/faker -D

Read from your OpenAPI descriptions and output generated code:

# can be http url or a file path on your machine, support both yaml and json.
npx msw-auto-mock http://your_openapi.json -o ./mock.js

See here for generated code with GitHub API example. The msw mocking handlers was generated by following command:

npx msw-auto-mock https://raw.githubusercontent.com/github/rest-api-description/main/descriptions/ghes-3.3/ghes-3.3.json --output ./example/ghapi.js

Integrate with msw, see Mock Service Worker's doc for more detail:

# Install msw
yarn add msw --dev

# Init service worker
npx msw init public/ --save

Then import those mock definitions in you app entry:

import { startWorker } from './mock';

if (process.env.NODE_ENV === 'development') {
  startWorker();
}

Run you app then you'll see a successful activation message from Mock Service Worker in your browser's console.

-o, --output: specify output file path or output to stdout.
-m, --max-array-length <number>: specify max array length in response, default value is 20, it'll cost some time if you want to generate a huge chunk of random data.
-t, --include <keywords>: specify keywords to match if you want to generate mock data only for certain requests, multiple keywords can be seperated with comma.
-e, --exclude <keywords>: specify keywords to exclude, multiple keywords can be seperated with comma.
--base-url: output code with specified base url or fallback to server host specified in OpenAPI.
--node: by default it will generate code for browser environment, use this flag if you want to use it in Node.js environment.
-c, --codes <keywords>: comma separated list of status codes to generate responses for
-h, --help: show help info.