JS：将多回调函数重构为Promise

Question

I was wondering if someone knows a good way to refactor the following function into a more promise-esque function:

function runProcess(processStarted, processFinished) {
   getProcessId(processStarted)
   doABunchOfAsyncLogic(processFinished)
}

It is invoked like this:

runPromise(function handleStart(){...}, function handleEnd(){...})

Answer 1

This is not a good use-case for promises, because by its nature you need two callbacks: One for starting, one for finishing. But promises are one-offs: Once settled, they can't be re-settled or similar.

You can do it, by returning an array of two promises, or an object with the individual promises for "start" and "finish":

function runProcess() {
    return {
        start: new Promise(...),
        finish: new Promise(...)
    };
}

...but it's not a natural promise use-case.

I'd probably expect the process to start during the function call, and only its end to be promise-ified.