Promise.try without bluebird

Question

I am trying to re-create bluebird's promise.try function, is this essentially the same?

function promiseTry(callback) {
  let error;
  let value;
  try {
    value = callback();
  } catch (e) {
    error = e;
  }
  return new Promise((resolve, reject) => {
    if (error) {
      reject(error);
      throw error;
    }
    resolve(value);
  });
}

const x = promiseTry(() => {
  throw new Error('hi');
});

How can I simply implement bluebird's Promise.try with a native node Promise?

Answer 1

This should be equivalent:

function promiseTry(callback) {
  return new Promise((resolve, reject) => {
    try {
      resolve(callback())
    } catch(e) {
      reject(e);
    }
  });
}

const x = promiseTry(() => {
  throw new Error('hi');
});

x.then(() => console.log("Promise resolved")).catch(err => console.log("Promise rejected:", err.message));

If you can use async/await, async functions have this behavior implicitly. Any synchronous exceptions thrown in an async function are converted into a promise rejection.