Does it allow for mocking on demand?

[adammo94]

I want to mock a POST request on demand (when test presses a button) is it possible here or should I use other library?

[kettanaito]

Hey, @adammo94.

You can control whether mocking is enabled on runtime by starting or stopping the worker whenever you need.

• worker.start()
• worker.stop()

Here's how I'd implement an on-demand mocking as you described:

// mocks/browser.js
import { setupWorker } from 'msw'
import { handlers } from './your-handlers'

// Create the worker instance but don't start it yet.
// This means that the mocking is configured but not active.
export const worker = setupWorker(...handlers)

// ui.js
import { worker } from './mocks/browser'

btn.addEventListener('click', () => {
  // Start the worker to enable requests interception.
  worker.start()
})

Note that calling worker.start() returns a Promise. You may want to await that promise resolution to ensure that the mocking is enabled successfully.

[kettanaito]

Hey, @adammo94. I'm marking this as the answer to your question. Please let me know in the comment below if there's still something unclear.