简化if else语句

Question

I have some functionality dependent on many conditions. All variables in conditional statements are boolean variables and the code is the following and I don't like it:

    if (userHasMoreThanOneMarket && isOnlyMarketSelected || !userHasMoreThanOneMarket && userHasMoreThanOneAgency) {
        if (isOnlyAgencySelected) {
            //do case 1

        } else if (noAgencySelected && isOnlyMarketSelected) {
            //do case 2
        }
    }

Is there a way to make it more understandable and nice?

Answer 1

That's about as concise as you're going to get with JavaScript. I suppose if you really wanted to, you could create variables to store your binary options:

var multiMarketOneSelected = userHasMoreThanOneMarket && isOnlyMarketSelected;
var singleMarketMultiAgency = !userHasMoreThanOneMarket && userHasMoreThanOneAgency;

if (multiMarketOneSelected || singleMarketMultiAgency) {
    if (isOnlyAgencySelected) {
        //do case 1

    } else if (noAgencySelected && isOnlyMarketSelected) {
        //do case 2
    }
}

Though I don't really know if you gain much readability from that.

Answer 2

Your code seems fine, but if you don't like it you could do something like this (note that the only improvement here is style, if you like it better):

function check(){
    return {
        valid: userHasMoreThanOneMarket && isOnlyMarketSelected || !userHasMoreThanOneMarket && userHasMoreThanOneAgency,
        case: [
           isOnlyAgencySelected,
           noAgencySelected && isOnlyMarketSelected
        ]
    };
}

var conditions = check();
if (conditions.valid) {
    if (conditions.case[0]) {
        //do case 1
    } else if (conditions.case[1]) {
        //do case 2
    }
}

Answer 3

Some things I would try to make the code more readable:

1. Initialise the variables in a way that you don't have to negate them again. So !userHasMoreThanOneMarket becomes userHasOneMarket
2. isOnlyMarketSelected sounds redundant to me. And you are checking it in the outer if-clause and the inner again.
3. You probably have a lot of code above this code snippet to initialise and set all this boolean values. Try return; statements after each variable to get rid of if-conditions.

I hope this helps.