JS Snippets

spawn-async.mjs

import { spawn } from "node:child_process";
import { on, once } from "node:events";

async function spawnAsync(...args) {
  const subprocess = spawn(...args);
  /** @see https://github.com/sindresorhus/nano-spawn/blob/cc231e2c7/source/spawn.js#L24-L26 */
  subprocess.once("error", () => {});

  const until = ["spawn", "close"].reduce((out, event) => {
    out[event] = once(subprocess, event);
    return out;
  }, Object.create(null));

  await until.spawn;

  const result = ["stdout", "stderr"].reduce((out, stdio) => {
    out[stdio] = "";

    const stream = subprocess[stdio];

    if (stream) {
      stream.setEncoding("utf8");

      const task = Array.fromAsync(
        on(stream, "data", { close: ["close"] }),
      ).then((chunks) => {
        const output = chunks.join("");
        out[stdio] = stdio === "stdout" ? output.trimEnd("\n") : output;
      });

      out[stdio] = task;
    }

    return out;
  }, Object.create(null));

  await Promise.all(Object.values(result));
  await until.close;

  return result;
}

export default spawnAsync;

unicode-identifiers.mjs

#!/usr/bin/env node

import { basename } from "node:path";
import { writeFile } from "node:fs/promises";

const isStart = /^\p{ID_Start}$/u;
const isPart = /^\p{ID_Continue}$/u;

const lines = ["codepoint\tcharacter\ttype"];

for (let cp = 0; cp <= 0x10ffff; cp++) {
  if (cp >= 0xd800 && cp <= 0xdfff) continue;

  const char = String.fromCodePoint(cp);
  const start = isStart.test(char);
  const part = isPart.test(char);

  if (start || part) {
    const hex = `U+${cp.toString(16).toUpperCase().padStart(4, "0")}`;
    const type = start ? "Start" : "Continue";
    lines.push(`${hex}\t${char}\t${type}`);
  }
}

const output = new URL("unicode_identifiers.tsv", import.meta.url);

await writeFile(output, lines.join("\n"), "utf8");

console.log(
  `Done. ${lines.length - 1} characters written to ${basename(output.toString())}`,
);