减少if else语句的数量？

Question

I have some JavaScript, when a user enters in 10 digits in the phone field,it checks whether the country field has been populated so that it can assign a country code to it. See code below.

if (Country != null) {
    var CountryName = Country[0].name;
    var CountryId = Country[0].id;
    var CountryType = Country[0].entityType;
    if (CountryName == "United States of America") {
        PhoneTemp = "+1 " + "(" + PhoneTemp.substr(0, 3) + ") " + PhoneTemp.substr(3, 3) + " - " + PhoneTemp.substr(6, 4);
    } else if (CountryName == "India") {
        PhoneTemp = "+91 " + PhoneTemp.substr(0, 4) + " " + PhoneTemp.substr(4, 6);
    }
}

If i do it this way ill end up with a 100+ else if, is there a nicer way of doing it?

Answer 1

You can use switch or you can use Jquery $.inArray(val, array)

• http://www.w3schools.com/js/js_switch.asp
• http://api.jquery.com/jquery.inarray/

Answer 2

I would go for a map to abstract the country logic

var countryMap = {
  'USA': usaLogic,
  'FR': frLogic
};

function usaLogic(number) {
   return "+1 " + "(" + number.substr(0, 3) + ") " + number.substr(3, 3) + " - " + number.substr(6, 4);
}

function frLogic(number) {
   return ".....";
}

Then you can reduce your if statement to the following:

if (countryMap[CountryName]) {
   PhoneTemp = countryMap[CountryName](PhoneTemp)
}

Answer 3

You can make an array or structure with countries and the phone prefix.

var Countries = ['India', 'France', 'Spain'];
var Prefixes = [91, 32, 34];

And with it you can save all if-else statements just calling the correct key in array.

Answer 4

Create a dictionary of country converters.

PhoneCountryConverters["India"] = function(PhoneTemp) { return  "+91 " + PhoneTemp.substr(0, 4) + " " + PhoneTemp.substr(4, 6);}

usage:

PhoneTemp = PhoneCountryConverters[Country[0].name](PhoneTemp);

PhoneCountryConverters will have an entry for each country, and you eliminate if statements altogether.

Answer 5

Hi brother you can use two arrays like this :

var CountriesPrefix = {'usa': '+1','India': '+2', 'morocco': '+212'};
var Countries = ['usa', 'India', 'morocco'];
var CountryName='usa';

if($.inArray(CountryName, countries)==0){ //The country is in array
    var PhoneTemp = countries_prefix[CountryName];
}

Using associative array here will reduce the pain of indexs between arrays by using the keys (the keys here are the Countries names).