move to correct structure

instance/src/lib/utils.ts

@@ -0,0 +1,43 @@
+import { TextLineStream } from "https://deno.land/std@0.208.0/streams/mod.ts";
+
+export function channel<T>() {
+	const inner = {
+		queue: [] as T[],
+		resolver: null as (() => void) | null,
+	};
+	const send = (item: T) => {
+		inner.queue.push(item);
+		if (inner.resolver === null) return;
+		inner.resolver();
+		inner.resolver = null;
+	};
+	const receive = async () => {
+		if (inner.queue.length < 1) await new Promise<void>((res) => inner.resolver = res);
+		const [head] = inner.queue.splice(0, 1);
+		return head;
+	};
+	return { send, receive };
+}
+
+export function* range(from: number, to: number) {
+	while (from < to) yield from++;
+}
+
+export async function exists(path: string) {
+	try {
+		await Deno.stat(path);
+		return true;
+	} catch (_) {
+		return false;
+	}
+}
+
+export async function next<T>(readable: ReadableStream<T>) {
+	for await (const item of readable) return item;
+}
+
+export function lines(readable: ReadableStream<Uint8Array>) {
+	return readable
+		.pipeThrough(new TextDecoderStream())
+		.pipeThrough(new TextLineStream());
+}