Refresh profiles on app start (at most every 12 hours)

ts/util/iterables.ts

@@ -0,0 +1,68 @@
+// Copyright 2021 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+/* eslint-disable max-classes-per-file */
+
+export function map<T, ResultT>(
+  iterable: Iterable<T>,
+  fn: (value: T) => ResultT
+): Iterable<ResultT> {
+  return new MapIterable(iterable, fn);
+}
+
+class MapIterable<T, ResultT> implements Iterable<ResultT> {
+  constructor(
+    private readonly iterable: Iterable<T>,
+    private readonly fn: (value: T) => ResultT
+  ) {}
+
+  [Symbol.iterator](): Iterator<ResultT> {
+    return new MapIterator(this.iterable[Symbol.iterator](), this.fn);
+  }
+}
+
+class MapIterator<T, ResultT> implements Iterator<ResultT> {
+  constructor(
+    private readonly iterator: Iterator<T>,
+    private readonly fn: (value: T) => ResultT
+  ) {}
+
+  next(): IteratorResult<ResultT> {
+    const nextIteration = this.iterator.next();
+    if (nextIteration.done) {
+      return nextIteration;
+    }
+    return {
+      done: false,
+      value: this.fn(nextIteration.value),
+    };
+  }
+}
+
+export function take<T>(iterable: Iterable<T>, amount: number): Iterable<T> {
+  return new TakeIterable(iterable, amount);
+}
+
+class TakeIterable<T> implements Iterable<T> {
+  constructor(
+    private readonly iterable: Iterable<T>,
+    private readonly amount: number
+  ) {}
+
+  [Symbol.iterator](): Iterator<T> {
+    return new TakeIterator(this.iterable[Symbol.iterator](), this.amount);
+  }
+}
+
+class TakeIterator<T> implements Iterator<T> {
+  constructor(private readonly iterator: Iterator<T>, private amount: number) {}
+
+  next(): IteratorResult<T> {
+    const nextIteration = this.iterator.next();
+    if (nextIteration.done || this.amount === 0) {
+      return { done: true, value: undefined };
+    }
+    this.amount -= 1;
+    return nextIteration;
+  }
+}