lolcat imitation for deno

lol.ts

import { BufReader } from "https://deno.land/[email protected]/io/bufio.ts";

const stdin = BufReader.create(Deno.stdin);

const decoder = new TextDecoder("utf-8", {fatal: true});
const encoder = new TextEncoder();

const colors = [
  [128, 255, 128],
  [128, 128, 255],
  [128, 255, 255],
  [255, 128, 128],
  [255, 255, 128],
  [255, 128, 255],
].map(([r, g, b]) => encoder.encode(`\x1b[38;2;${r};${g};${b}m`));
let cnt = 0;

let b: Uint8Array | null;
let buf: number[] = []; // 通常文字のバッファ(マルチバイトをちゃんと処理するため)
while ((b = await stdin.peek(1)) !== null) {
  await stdin.readByte();
  if (b[0] === 0x1b) {
    const buf = [0x1b];
    while (await stdin.peek(1) !== null) {
      const b = (await stdin.readByte())!;
      buf.push(b);
      if ((0x41 <= b && b <= 0x5a) || (0x61 <= b && b <= 0x7a)) {
        await Deno.stdout.write(Uint8Array.from(buf));
        break;
      }
    }
  } else {
    await Deno.stdout.write(colors[cnt++ % colors.length]);
    buf.push(b[0]);
    try {
      const arr = Uint8Array.from(buf);
      decoder.decode(arr);
      await Deno.stdout.write(arr);
      buf = [];
    } catch {
    }
  }
}