error-handling.js

function timeout(timeInMs, wontDo) {
  return new Promise((resolve, reject) => {
    if (wontDo === true) {
      reject(Error("I wont do!"));
    }
    setTimeout(resolve(`timeout finished ${timeInMs}`), timeInMs);
  });
}

async function A() {
  // add true to second argument to make timeout fail/reject
  // await timeout(300, true)

  await timeout(300);
  //     throw Error('something bad')

  console.log("done with A");
  return "A";
}

async function B() {
  try {
    await timeout(100);
    await A();
    // throw Error('something bad')

    console.log("done with B");
    return "B";
  } catch (error) {
    console.error(`error in B: ${error}`);

    // you can throw the error further down
    // then this async function with reject or throw error.
    // throw error
  }
}

async function C() {
  try {
    await timeout(100);
    await B();
    // await A()
    // throw Error('something bad')

    console.log("done with C");
    return "C";
  } catch (error) {
    console.error("error in C: ", error);
  }
}

async function main() {
  try {
    await timeout(300);
    await C();
    console.log("done with main");
    return "main";
  } catch (error) {
    console.error("error in main: ", error);
  }
}

main()
  .then(console.log)
  .catch(console.error)
  .finally(() => console.log("done"));