There's a lot of focus around doing this on the front end. And it's true using UIs are doused in reactivity and asynchrony. Also, React was the iPod moment for functional programming along with Flux/Redux. Anyways, there is plenty of application for this pattern in a sufficiently effectual backend. And for backends that don't even have a lot of effects, lifting them to the top would go a long way to improve the test cases by omitting the mocks.
https://github.com/orourkedd/effects-as-data
https://medium.com/javascript-scene/mocking-is-a-code-smell-944a70c90a6a
https://redux-saga.js.org/
https://erock.io/simplify-testing-async-io-javascript/
https://redux-loop.js.org/docs/tutorial/Tutorial.html
Elm Architecture
https://github.com/dubzzz/fast-check
There's a lot of focus around doing this on the front end. And it's true using UIs are doused in reactivity and asynchrony. Also, React was the iPod moment for functional programming along with Flux/Redux. Anyways, there is plenty of application for this pattern in a sufficiently effectual backend. And for backends that don't even have a lot of effects, lifting them to the top would go a long way to improve the test cases by omitting the mocks.