refactor(mutation): remove mutation.cancel (#3225)

as it wasn't really aborting the request - there is no AbortSignal for Mutations atm.

Author: TkDodo

docs/src/pages/guides/migrating-to-react-query-4.md

@@ -217,18 +217,9 @@ The `useQueries` hook now accepts an object with a `queries` prop as its input.
 ```
 
 
-### Removed undocumented methods from the `queryClient` and `query`
+### Removed undocumented methods from the `queryClient`, `query` and `mutation`
 
-The methods `cancelMutatations` and `executeMutation` on the `QueryClient` were undocumented and unused internally, so we removed them. Since they were just wrappers around methods available on the `mutationCache`, you can still use the functionality.
-
-```diff
-- cancelMutations(): Promise<void> {
--   const promises = notifyManager.batch(() =>
--     this.mutationCache.getAll().map(mutation => mutation.cancel())
--   )
--   return Promise.all(promises).then(noop).catch(noop)
-- }
-```
+The methods `cancelMutatations` and `executeMutation` on the `QueryClient` were undocumented and unused internally, so we removed them. Since it was just a wrapper around a method available on the `mutationCache`, you can still use the functionality of `executeMutation`
 
 ```diff
 - executeMutation<
@@ -243,7 +234,7 @@ The methods `cancelMutatations` and `executeMutation` on the `QueryClient` were
 - }
 ```
 
-Additionally, `query.setDefaultOptions` was removed because it was also unused.
+Additionally, `query.setDefaultOptions` was removed because it was also unused. `mutation.cancel` was removed because it didn't actually cancel the outgoing request.
 
 ### TypeScript
 

src/core/mutation.ts

@@ -5,7 +5,6 @@ import { getLogger } from './logger'
 import { notifyManager } from './notifyManager'
 import { Removable } from './removable'
 import { canFetch, Retryer, createRetryer } from './retryer'
-import { noop } from './utils'
 
 // TYPES
 
@@ -150,14 +149,6 @@ export class Mutation<
     }
   }
 
-  cancel(): Promise<void> {
-    if (this.retryer) {
-      this.retryer.cancel()
-      return this.retryer.promise.then(noop).catch(noop)
-    }
-    return Promise.resolve()
-  }
-
   continue(): Promise<TData> {
     if (this.retryer) {
       this.retryer.continue()

src/core/mutationCache.ts

@@ -106,7 +106,6 @@ export class MutationCache extends Subscribable<MutationCacheListener> {
 
   remove(mutation: Mutation<any, any, any, any>): void {
     this.mutations = this.mutations.filter(x => x !== mutation)
-    mutation.cancel()
     this.notify({ type: 'removed', mutation })
   }
 

src/core/tests/mutations.test.tsx

@@ -369,33 +369,6 @@ describe('mutations', () => {
     consoleMock.mockRestore()
   })
 
-  test('cancel mutation should not call mutationFn if the current retrier is undefined', async () => {
-    const mutationFn = jest.fn().mockImplementation(async () => {
-      await sleep(20)
-      return 'data'
-    })
-
-    const observer = new MutationObserver(queryClient, {
-      mutationKey: ['key'],
-      mutationFn,
-    })
-
-    observer.mutate()
-    const mutation = queryClient
-      .getMutationCache()
-      .find({ mutationKey: ['key'] })!
-    await sleep(10)
-
-    // Force current mutation retryer to be undefined
-    // because not use case has been found
-    mutation['retryer'] = undefined
-    mutationFn.mockReset()
-    await mutation.cancel()
-
-    await sleep(30)
-    expect(mutationFn).toHaveBeenCalledTimes(0)
-  })
-
   test('reducer should return the state for an unknown action type', async () => {
     const observer = new MutationObserver(queryClient, {
       mutationKey: ['key'],