引数のディレクトリを監視し、一定時間操作がなかったら処理を行うdeno

dirWatcher.ts

// deno run --allow-read --allow-run dirWatcher.ts /absolute/path/watch/

const targetEventKind = ["create", "modify", "rename", "remove"];
// 操作が止まったと判断する時間
const delayMsec = 3000;

let promise: Promise<any> | undefined;
let resolve;
let timeoutId;

const targetDir = Deno.args[0];
console.log(targetDir);

for await (const fsEvent of Deno.watchFs(targetDir)) {
  if (!targetEventKind.includes(fsEvent.kind)) {
    continue;
  }

  if (!resolve) {
    const withResolvers = Promise.withResolvers();
    promise = withResolvers.promise;
    resolve = withResolvers.resolve;
    // fire and forget
    run().catch();
  }

  if (resolve) {
    clearTimeout(timeoutId);
    timeoutId = setTimeout(resolve, delayMsec);
  }
}

async function run() {
  if (!promise) {
    return;
  }
  await promise;
  promise = undefined;
  resolve = undefined;
  await doWhat();
}

async function doWhat() {
  // やりたい処理をここに書く
  console.log("do what you want");
}