feat!: initial commit

Signed-off-by: João Augusto Costa Branco Marado Torres <torres.dev@disroot.org>

1 files changed, 52 insertions, 0 deletions

diff --git a/src/utils/iterator.ts b/src/utils/iterator.ts
new file mode 100644
index 0000000..fa58fc9
--- /dev/null
+++ b/src/utils/iterator.ts
@@ -0,0 +1,52 @@
+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);
+}