Question

I have seen posts like Declaring Multiple Variables in JavaScript that focus on unique variables (and lots of them), but I am looking at lots of non-unique variables, for example I want to do a much larger version of this…

            var rep;
            var state_def, state_MA, state_WY, state_TN = 'joeblow';
            var state_AZ, state_TX = 'moefoe';
            var state_MT, state_OR = 'growmo';
            var state_OK, state_LA = 'billyjoe';
            var state_WA, state_NM, state_MS = 'messytess';
            var state_VA, state_NY = 'slickrick';
            var state_CA = 'icecube';

            //or
            var state_def = state_MA = state_WY = state_TN = 'joeblow';

Just to understand, I am using a switch like so…

switch (capitalise(data.regionName)) {
                case 'Arizona': rep = state_AZ; break;
                case 'Texas': rep = state_TX; break;
                case 'Montana': rep = state_MT; break;
                case 'Oregon': rep = state_OR; break;
                case 'New Mexico': rep = state_NM; break;
                case 'Mississippi': rep = state_MS; break;
                case 'Oklahoma': rep = state_OK; break;
                case 'Louisiana': rep = state_LA; break;
                case 'Washington': rep = state_WA; break;
                case 'Massachusetts': rep = state_MA; break;
                case 'Wyoming': rep = state_WY; break;
                case 'Tennessee': rep = state_TN; break;
                case 'Virginia': rep = state_VA; break;
                case 'Illinois': rep = state_IL; break;
                case 'Nevada': rep = state_NV; break;
                default: rep = state_def; break;
            };

This will have several thousand zipcodes as well, so a secondary switch for this. That is why declaring the state (or zip) variable / user association as short as possible is needed. But I also do not want to fall into any pitfalls I might be unaware of. This works right now with the exception of the default: rep = state_def; break; returning as undefined. Also, does not work in IE8.

Answer 1

I suggest replacing your switch with a mapping:

var reps = {
    'Arizona': state_AZ,
    'Texas': state_TX,
    // etc.
};

// then you can do this:
var rep = reps[capitalize(data.regionName)];

Later, you could even download that mapping (including the values) as a JSON object or something from a server or other data source.

Notice also, that most of your state_* variables are undefined. I don’t know if this is what you intended. If you only have data for some states, it might be better to build the data structure directly:

var reps = {
    'Arizona': undefined, // or just omit from mapping
    'Texas': 'moefoe',
    // etc.
};

and dispense with all the state_* variables.