feat: add mutation api #202
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experimental mutation API
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Falls back to the current injector
…d out about exhaust semantics
rainerhahnekamp
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This review consists of two parts. Things that should be addressed before we merge it, and things that can be done later, as additional features.
I've added a TODO prefix to all my comments that fall into the second category (which could be done later).
Here's a summary, where we could have separate Issues and PR contributions.
- #220
rxMutateas fully standalone function which would also work outside the SignalStore - Documentation in Docusaurus
- Refactoring of Tests (depends on standalone
rxMutation, we can do more directly in that file and don’t have to go through the complete SignalStore. - Allow
withMutationsto expose more tracking data of the mutation, likeisPending,hasValue. - E2E Tests for Mutation Demo
- Standalone and Promise-based
mutation - #221 Standalone
httpMutationin the same manner ashttpResource. - Redesign of flatten operator: Should probably have a callback telling that a certain input has been skipped.
…essing to IsPending
rainerhahnekamp
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This introduces `withMutations` as a new SignalStore feature,
with initial support for RxJS-powered mutations via `rxMutation`.
Example:
```typescript
export const CounterStore = signalStore(
withState({ counter: 0 }),
withMutations((store) => ({
increment: rxMutation({
operation: (value: number) => {
return httpClient.post('counter/increase', { value });
},
onSuccess: (result) => {
patchState(store, { counter: result });
},
}),
})),
);
const counterStore = inject(CounterStore);
counterStore.increment(1);
console.log(counterStore.counter()); // prints 1
````
---
- Mutations is the term the Angular team uses for a potential upcoming
feature that complements *resources* (which are read-only). Mutations
enable writing data back to the server.
- To align with this mutation-based mindset, we are introducing custom
mutation support in the toolkit.
- The design is inspired by @markostanimirovic’s prototype:
https://github.com/markostanimirovic/rx-resource-proto
- Thanks to Marko for consulting with the NgRx team, and to Alex
Rickabaugh (@alxhub) for the core mutation design.
- We also took ideas from TanStack Query's mutation feature:
https://tanstack.com/query/latest
---
This commit lays the foundation for further expansion of mutation
support in SignalStore.
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rxMutation creates a mutation function in the store, delegating to a function/ method returning an observable, and takes care of race conditions by internally using mergeMap (default), switchMap, concatMap, or exhaustMap.
mutation also creates an async mutation function, delegating to a function/ method returning an observable. When the async function is awaited without throwing an exception, the caller can safely assume that it has been executed. However, here, the consumer is responsible for preventing race conditions.