efate VS data

Efate is actually the second test fixture library I've written and there were several lessons I learned after using the first iteration for several years myself. The first version was influenced a great deal by factor_girl (called factory_bot now), with a heavy dependency on strings to define and create the fixtures. It also wasn't very modular. You couldn't just import a specific fixture, you had to bring in the whole library. And it wasn't very extensible, if you needed to define custom behavior for how a field should be created, it wasn't very pretty.

Efate is a modern test fixture generator, design for use in JavaScript or Typescript. generates modular fixtures that can be imported in and reduces the use of strings for both fixture definition and usages. It allows you to override specific fields during fixture creation and returning full object definitions with dummy data for other fields. It is also extensible, allowing you to create custom field generator definitions.

It supports both REST and GraphQL APIs, it can delay the response of mocked API endpoints so the endpoint feels more real-life, it has it's own in-memory database with @msw/data package for more complex querying (e.g, searching, sorting), it can also run mocks in NodeJS environment instead of Service Worker (really useful for testing). Next, let's take a look at which problems msw can solve and how.

Next steps mswjs/data

Today we are proud to announce the Data library—a standalone package to model and query data in your tests and beyond. Although the project is at the early stage of development and doesn't solve every problem right away, letting you try it out and gather your feedback is crucial for us to refine and shape the future experience.