Variable: fetchState

Imported from @react-logic/utils

const fetchState: {<F, T>(build, config?): ReactiveReturn<F, T>; callable: <Args, T>(build, config?) => FetchStateAccessor<T, Args>; }

Defined in: utils/src/lib/fetch-state.ts:530

Reactive fetch with cancellation, a discriminated loading/result/error state, and HTTP status on success/failed.

The build callback returns either a URL string (shorthand for a GET) or a full FetchStateRequest descriptor. Returning null / undefined / empty string skips the fetch for that tick. The optional second argument supplies static defaults merged into every request — per-call wins on conflict; headers deep-merge.

Reactive (the default): the build callback tracks every signal it reads. The fetch re-fires whenever a tracked signal changes.

// No input — depends on outer signals.
data = fetchState(() => {
  const id = this.userId();
  return id ? `/users/${id}` : null;
});
data();          // → FetchStateValue
data.fetch();    // → re-fetch (same URL, current signals)

// Input variant — `.fetch(v)` writes the wrapped input signal,
// re-triggering the build with the new value.
results = fetchState((q = '') => q ? `/search?q=${q}` : null);
results.fetch('react');   // sets input, fires
results.fetch();          // refetch with current input
results();                 // → FetchStateValue

Imperative — see fetchState.callable. The build callback only runs when you call .fetch(...); no signal tracking. The right shape for mutations and one-off triggers.

Type Declaration

Type Parameters

F

F extends (...args) => FetchStateBuilderResult<T>

The build-callback signature.

T

T = unknown

The parsed response type.

Parameters

build

F

config?

FetchStateConfig<T>

Returns

ReactiveReturn<F, T>

callable

callable: <Args, T>(build, config?) => FetchStateAccessor<T, Args>

Imperative companion. The build callback only runs when .fetch(...) is called — never reactively. Same accessor shape as the reactive form.

const postComment = fetchState.callable((message: string) => ({
  url: '/api/comments',
  method: 'POST',
  body: { message },     // plain object — auto-stringified
}));

postComment.fetch('hello world');   // fires the request
postComment();                       // reads FetchStateValue
postComment.fetch();                 // re-runs with 'hello world'

Calling .fetch(...) again before the previous request resolves aborts the previous in-flight request. A no-arg .fetch() before any .fetch(...args) is a no-op (no args to fire with).

Type Parameters

Args

Args extends readonly unknown[]

The build callback's argument tuple.

T

T = unknown

The parsed response type.

Parameters

build

(...args) => string | FetchStateRequest<T>

config?

FetchStateConfig<T>

Returns

FetchStateAccessor<T, Args>