我应该如何在退货声明中处理这个有条件的承诺？

Question

I need to perform several functions, some of which may include asynchronous callbacks (based on conditions) when a button is clicked.

I have a submit button that I do not want to prevent default behavior on to perform these operations (ieepreventDefault())

Instead, I need to simply return true or false:

$('#submitBtn').click(function(e) {
    return mdl.entry(e);
});

var mdl: {
  entry: function(evt) {
    if (condition) {
      return ...
    } else {
      return anotherFunction();
    }
  }
}

function anotherFunction() {
  // This function could potentially involve one or more 
  // asynchronous requests
  some.func(obj).then(function(result) {
    ... do stuff
  });
}

What's the best way to deal with this? I know I can poll a global variable, or set a variable and trigger a click event:

$('#submitBtn').click(function(e) {
    if (!safeToSubmit) {
      e.preventDefault();
      mdl.entry(e); 
      // when finished, it sets safeToSubmit to true
      // and triggers a click on the button 
    } 
});

I hope my issue makes sense. Above is dummy code. Probably 10 different functions that conditionally make asynchronous calls. Perhaps a best practices question? I can make it work... I just want a better way :)

Answer 1

One way to deal with this is to always return a Promise. For synchronous functions instead of return someValue you return Promise.resolve(someValue)

Then you can deal with the return value the same way for everything with something like:

mdl.entry(e)
.then((ret) => { //do stuff with ret })

EDIT:

I am imagining something like this:

$('#submitBtn').click(function(e) {
    mdl.entry(e)
    .then((ret) => { /* whatever is supposed to be donw with the return */ })
});

var mdl = {
entry: function(evt) {
    if (condition) {
        var res = someSynchronousFunction(evy)
        return Promise.resolve(res)
    } else {
        return anotherFunction();
    }
}
}

function anotherFunction() {
    return someAsyncFunction(obj).then(function(result) {  
    //... do stuff and return a value
    // someAsyncFunction will return a promise that resolves to this value
    });
}