init

src/lib/utils.ts

@@ -0,0 +1,49 @@
+import { basename } from "https://deno.land/std@0.223.0/path/basename.ts";
+
+export function log_from(meta: ImportMeta) {
+	const url = new URL(meta.url);
+	const file = basename(url.pathname);
+	return (...args: unknown[]) => console.log(`[${file}]`, ...args);
+}
+
+export function last<T>(items: Iterable<T>) {
+	let result = null as T | null;
+	for (const item of items) result = item;
+	return result;
+}
+
+export function days_to_ms(days: number) {
+	const ms_per_day = 24 * 60 * 60 * 1000;
+	return days * ms_per_day;
+}
+
+export async function collect<T>(iterator: AsyncIterable<T>) {
+	const collected = [] as T[];
+	for await (const item of iterator) collected.push(item);
+	return collected;
+}
+
+export type Channel<T = void> = ReturnType<typeof channel<T>>;
+export function channel<T = void>() {
+	const queue = [] as T[];
+	let resolve_next = null as null | ((value: T) => void);
+
+	async function receive() {
+		if (resolve_next !== null) throw new Error("Receiving twice concurently.");
+		if (queue.length > 0) return queue.splice(0, 1)[0];
+		const result = await new Promise<T>((resolver) => resolve_next = resolver);
+		resolve_next = null;
+		return result;
+	}
+
+	function send(item: T) {
+		if (resolve_next === null) queue.push(item);
+		else resolve_next(item);
+	}
+
+	return { send, receive };
+}
+
+export async function wait(ms: number) {
+	await new Promise((resolver) => setTimeout(resolver, ms));
+}