[ecmascript] timeout promise and inverval async iterator

async-timeout-interval.js

export const timeout = (msec, ...args) => new Promise(f => setTimeout(f, msec, args));
export const interval = (msec, ...args) => ({
  [Symbol.asyncIterator]() {
    const rs = [];
    const id = setInterval(() => rs.shift()?.call(undefined, {value: args, done: false}), msec);
    return {
      next() {
        return new Promise(f => rs.push(f));
      },
      throw() {
        //console.info("throw");
        clearInterval(id);
        return {value: args, done: true};
      },
      return() {
        //console.info("return");
        clearInterval(id);
        return {value: args, done: true};
      },
    };
  }
});


if (import.meta.main) (async function example() {
  console.log(...await timeout(100, "hello"));

  let i = 0;
  for await (const v of interval(500, "world")) {
    if (i++ == 5) break;
    console.log(...v);
  }
})().catch(console.error);