how to create and assign a value to a variable created dynamically?

Question

I\'m trying to get this to work:

function whatever(arg) {
  eval(arg) + \'_group\' = [];
}

The purpose is to have only 1 function instead h

Answer 1

function whatever(arg) {
  window[arg + '_group'] = [];
}

This will set a_group, b_group as global variable.

To access those variable use:

window['a_group'], window['b_group'] and so on.

According to edit

In your switch you should use break;.

switch(field_name) {
    case 'states':
        use = 'state';
        break;
    case 'cities':
        use = 'city';
        break;
    case 'neighborhoods':
        use = 'neighborhood';   
        break;     
}

Using local Object (without window object) and better

var myObject = {};

function whatever(arg) {
  myObject[arg + '_group'] = [];
  // output: { 'a_group' : [], 'b_group' : [], .. }
}

// to set value
myObject[arg + '_group'].push( some_value );

// to get value
myObject[arg + '_group'];