What’s the correct way to handle promise rej…

Let’s say that I have this code:

function doSomething() {
    const foo = await new Promise((resolve, reject) => {
        //...
        reject();
    }).catch(error => {
        //I'd like to exit the doSomething function since the promise rejected
        return;//This only exists the this arrow funtion
    });

    console.log('Should not get to here if foo rejects');
}

If foo returns a rejected promise, then I’d like to exit doSomething(), but the code above does not do this. Instead since the error is caught, the code continues.

If I do not catch the rejected promise then I get an error: UnhandledPromiseRejectionWarning:

function doSomething() {
    const foo = await new Promise((resolve, reject) => {
        //...
        reject();
    });
    console.log('Should not get to here if foo rejects');
}

I know that I can do this, but this just feels messy:

function doSomething() {
    let exitFunction = false;
    const foo = await new Promise((resolve, reject) => {
        //...
        reject();
    }).catch(error => {
        //I'd like to exit the doSomething function since the promise rejected
        exitFunction = true;
    });

    if (exitFunction) {
       return;
    }

    console.log('Should not get to here if foo rejects');
}

So what is the best way to handle something like this? It’d be nice to be able to do this:

function doSomething() {
    const foo = await new Promise((resolve, reject) => {
        //...
        reject();
    });
    if (foo.rejected) {
        return;
    }
    console.log('Should not get to here if foo rejects');
}

Or even this:

function doSomething() {
    const foo = await new Promise((resolve, reject) => {
        //...
        reject();
    }).catch(error => {
        return function2;//Sort of like JS's `break loop2;`
    });
    console.log('Should not get to here if foo rejects');
}

Does anyone else feel my pain, if so what are is the best (cleanest) way to handle this?

Answer

I suggest using try/catch if you handle promises in async function

function promiseFunc() {
  return new Promise((resolve, reject) => {
    //...
    reject("error!");
  });
}

async function doSomething() {
  try {
    const foo = await promiseFunc();
  } catch (err) {
    console.log(err);
    return;
  }

  console.log("Should not get to here if foo rejects");
}

doSomething();

What’s the correct way to handle promise rejections so that the function exits?

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Answer