@krist7599555/ts-async-result
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[](https://www.npmjs.com/package/@krist7599555/ts-async-result)
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TypeScript
type Fn<I, O> = (arg: I) => O;
type InferValue<T> = Awaited<T>;
type InferError<T> = T extends AsyncResult<any, infer E> ? InferValue<E> : never;
/**
* # AsyncResult
* `Promise` Wrapper which provide errror type & more method
*
* ## Creation
* @example
* ```typescript
* AsyncResult.from(async () => fetch(str))
* AsyncResult.from(() => fetch(str))
* AsyncResult.from(fetch(str))
* AsyncResult.resolve("OK")
* AsyncResult.reject("Er")
* ```
* ## Transform
* @example
* ```typescript
* const out = await AsyncResult
* .from(async () => fetch(str))
* .assert(res => res.status == 200, (res) => new HttpError(res.status))
* .then(res => res.json())
* .tap(data => console.log("raw data:", data))
* .then(data => data || {})
* ```
* @example
* ```typescript
* const [ok, err] = await AsyncResult
* .from(async () => fetch(str))
* .pipe(
* res => res.status == 200 : res : AsyncResult.reject(new HttpError(res.status)),
* res => res.json(),
* data => data || {}
* )
* .pair()
* ```
* ## Limitation
* - 1. Async Function Will discard error type
* ```typescript
* const bad: Promise<never> = AsyncResult.from(async () => AsyncResult.reject('ERROR' as const));
* const better: AsyncResult<never, "ERROR"> = AsyncResult.from(() => AsyncResult.reject('ERROR' as const));
* ```
*/
export declare class AsyncResult<V, E> implements PromiseLike<V> {
private readonly promise;
constructor(fn: (resolve: Fn<V, void>, reject: Fn<E, void>) => void);
static NEVER: AsyncResult<never, never>;
static EMPTY: AsyncResult<void, never>;
static resolve<V>(value: V): AsyncResult<InferValue<V>, never>;
static reject<E>(error: E): AsyncResult<never, E>;
static from<T>(data: T | Fn<void, T>): AsyncResult<InferValue<T>, InferError<T>>;
toPromise(): Promise<V>;
then<Out>(onfulfilled: Fn<V, Out>): AsyncResult<InferValue<Out>, InferError<Out>>;
then<Out, Out2>(onfulfilled: Fn<V, Out>, onrejected: Fn<E, Out2>): AsyncResult<InferValue<Out> | InferValue<Out2>, InferError<Out> | InferError<Out2>>;
catch<Out>(fn: Fn<E, Out>): AsyncResult<V | InferValue<Out>, InferError<Out>>;
flatten(): AsyncResult<Awaited<Awaited<V>> | Awaited<Awaited<E>>, never>;
swap(): AsyncResult<Awaited<Awaited<E>>, Awaited<V>>;
pair(): AsyncResult<(V extends never ? never : [V, undefined]) | (E extends never ? never : [undefined, E]), never>;
guard<V2 extends V, E2>(fn: (val: V) => val is V2, on_false: E2 | Fn<V, E2>): AsyncResult<V2, E | E2>;
guard<V2, E2>(fn: (val: any) => val is V2, on_false: E2 | Fn<V, E2>): AsyncResult<V2, E | E2>;
guard<E2>(fn: Fn<V, boolean>, on_false: E2 | Fn<V, E2>): AsyncResult<V, E | E2>;
mapErr<E2>(fn: Fn<E, E2>): AsyncResult<V, Awaited<E2>>;
tap(fn: Fn<V, any>): AsyncResult<V, E>;
tapErr(fn: Fn<E, void | Promise<void>>): AsyncResult<V, E>;
fallback<V2>(value: V2): AsyncResult<V | V2, never>;
static all<T extends readonly unknown[] | [] | Record<string, any>>(data: T): AsyncResult<{
-readonly [P in keyof T]: InferValue<T[P]>;
}, InferError<T[keyof T]>>;
/**
* Gen Pipe With Code
* @exmaple
* ```javascript
* // GENERATE WITH THIS CODE
* function printPipes(n = 10) {
function _getPipe(n) {
const arr = Array.from({ length: n }).map((_, i) => i + 1);
const os = arr.map((i) => `O${i}`);
let fn = `pipe<${os.join(', ')}>`
let args = arr.map(i => `f${i}: Fn<InferValue<${i == 1 ? 'V' : `O${i-1}`}>, O${i}>`).join(', ')
let out = `AsyncResult<InferValue<O${n}>, E | InferError<${os.join(' | ')}>>`
return `${fn}(${args}): ${out};`
}
console.log(Array.from({ length: n }).map((_, i) => `// prettier-ignore\n` + _getPipe(i + 1)).join('\n'))
}
* ```
*/
pipe(): AsyncResult<V, E>;
pipe<O1>(f1: Fn<InferValue<V>, O1>): AsyncResult<InferValue<O1>, E | InferError<O1>>;
pipe<O1, O2>(f1: Fn<InferValue<V>, O1>, f2: Fn<InferValue<O1>, O2>): AsyncResult<InferValue<O2>, E | InferError<O1 | O2>>;
pipe<O1, O2, O3>(f1: Fn<InferValue<V>, O1>, f2: Fn<InferValue<O1>, O2>, f3: Fn<InferValue<O2>, O3>): AsyncResult<InferValue<O3>, E | InferError<O1 | O2 | O3>>;
pipe<O1, O2, O3, O4>(f1: Fn<InferValue<V>, O1>, f2: Fn<InferValue<O1>, O2>, f3: Fn<InferValue<O2>, O3>, f4: Fn<InferValue<O3>, O4>): AsyncResult<InferValue<O4>, E | InferError<O1 | O2 | O3 | O4>>;
pipe<O1, O2, O3, O4, O5>(f1: Fn<InferValue<V>, O1>, f2: Fn<InferValue<O1>, O2>, f3: Fn<InferValue<O2>, O3>, f4: Fn<InferValue<O3>, O4>, f5: Fn<InferValue<O4>, O5>): AsyncResult<InferValue<O5>, E | InferError<O1 | O2 | O3 | O4 | O5>>;
pipe<O1, O2, O3, O4, O5, O6>(f1: Fn<InferValue<V>, O1>, f2: Fn<InferValue<O1>, O2>, f3: Fn<InferValue<O2>, O3>, f4: Fn<InferValue<O3>, O4>, f5: Fn<InferValue<O4>, O5>, f6: Fn<InferValue<O5>, O6>): AsyncResult<InferValue<O6>, E | InferError<O1 | O2 | O3 | O4 | O5 | O6>>;
pipe<O1, O2, O3, O4, O5, O6, O7>(f1: Fn<InferValue<V>, O1>, f2: Fn<InferValue<O1>, O2>, f3: Fn<InferValue<O2>, O3>, f4: Fn<InferValue<O3>, O4>, f5: Fn<InferValue<O4>, O5>, f6: Fn<InferValue<O5>, O6>, f7: Fn<InferValue<O6>, O7>): AsyncResult<InferValue<O7>, E | InferError<O1 | O2 | O3 | O4 | O5 | O6 | O7>>;
pipe<O1, O2, O3, O4, O5, O6, O7, O8>(f1: Fn<InferValue<V>, O1>, f2: Fn<InferValue<O1>, O2>, f3: Fn<InferValue<O2>, O3>, f4: Fn<InferValue<O3>, O4>, f5: Fn<InferValue<O4>, O5>, f6: Fn<InferValue<O5>, O6>, f7: Fn<InferValue<O6>, O7>, f8: Fn<InferValue<O7>, O8>): AsyncResult<InferValue<O8>, E | InferError<O1 | O2 | O3 | O4 | O5 | O6 | O7 | O8>>;
pipe<O1, O2, O3, O4, O5, O6, O7, O8, O9>(f1: Fn<InferValue<V>, O1>, f2: Fn<InferValue<O1>, O2>, f3: Fn<InferValue<O2>, O3>, f4: Fn<InferValue<O3>, O4>, f5: Fn<InferValue<O4>, O5>, f6: Fn<InferValue<O5>, O6>, f7: Fn<InferValue<O6>, O7>, f8: Fn<InferValue<O7>, O8>, f9: Fn<InferValue<O8>, O9>): AsyncResult<InferValue<O9>, E | InferError<O1 | O2 | O3 | O4 | O5 | O6 | O7 | O8 | O9>>;
pipe<O1, O2, O3, O4, O5, O6, O7, O8, O9, O10>(f1: Fn<InferValue<V>, O1>, f2: Fn<InferValue<O1>, O2>, f3: Fn<InferValue<O2>, O3>, f4: Fn<InferValue<O3>, O4>, f5: Fn<InferValue<O4>, O5>, f6: Fn<InferValue<O5>, O6>, f7: Fn<InferValue<O6>, O7>, f8: Fn<InferValue<O7>, O8>, f9: Fn<InferValue<O8>, O9>, f10: Fn<InferValue<O9>, O10>): AsyncResult<InferValue<O10>, E | InferError<O1 | O2 | O3 | O4 | O5 | O6 | O7 | O8 | O9 | O10>>;
}
export {};