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export type MaybeIterable<T> = T | Iterable<T>;
export type NonEmptyArray<T> = [T, ...T[]];
export type AsyncYieldType<T> = T extends AsyncGenerator<infer U> ? U : never;
export function surelyIterable<T>(maybe: MaybeIterable<T>): Iterable<T> {
return typeof maybe === "object" && maybe !== null && Symbol.iterator in maybe
? maybe
: [maybe];
}
export async function* createAsyncIterator<T>(
promises: Promise<T>[],
): AsyncGenerator<T, void, void> {
for (const promise of promises) {
yield promise;
}
}
export function filterDuplicate<T, K>(
array: Iterable<T>,
key: (i: T) => K,
): T[] {
const seen = new Map<K, T>();
for (const i of array) {
const id = key(i);
if (!seen.has(id)) {
seen.set(id, i);
}
}
return Array.from(seen.values());
}
export async function findMapAsync<T, R>(
iter: Iterable<T>,
predicate: (value: T) => Promise<R>,
): Promise<R | undefined> {
const arr = Array.from(iter);
async function tryNext(index: number): Promise<R | undefined> {
if (index >= arr.length) {
return await Promise.resolve(undefined);
}
try {
return await predicate(arr[index]);
} catch {
return tryNext(index + 1);
}
}
return await tryNext(0);
}
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