Question

I’m having a logic problem with an implementation of combination rules in Javascript.

In short:

• I define which checkboxes cannot be ‘on’ together with eachother in a JSON object.
• If I click on measure 1 -> measures 7 and 8 get grayed out, this is correct.
• If I click on measure 4 -> measures 8, 9, 10 and 11 get grayed out, this is correct too.
• Now, if I click again on measure 4 -> measure 8 gets active again, but shouldn’t be, because the JSON ‘rules’ state that since measure 1 is still checked, measure 8 must be grayed.

What’s a smart way to solve this logic problem? Thanks in advance!

Basically, how do I remember that clicking ‘measure 1’ already disabled ‘measure 8’, so that toggling ‘measure 4’ won’t accidentally re-enable ‘measure 8’ with ‘measure 1’ still ‘on’?

All code here: https://gist.github.com/1055968

Interactive: http://jsfiddle.net/gnijholt/58zuR/

Answer 1

Well logically i’d do something like this:

• when you tick a checkbox, you create
  an object which stores the rules that
  are applied.
• when i untick a checkbox, i will
  remove that rule from the memory
  object and before unticking each
  checkboxes i’ll go through the memory
  object to see if there are any
  conflicting rules. If there is one
  conflicting rules, i do not gray out
  the checkbox.

I’m trying to implement this.

EDIT – i’v implemented my idea. here is a fiddle http://jsfiddle.net/Tvs7E/1/

function createObjectsWithRules(rulesApplied){
    var presentBlock = {};
    for (var checkboxid in rulesApplied){
      var presentCombos = rulesApplied[checkboxid];
       for(var key in presentCombos) {
           var obj = presentCombos[key];
           for(var prop in obj) {
              var s = obj[prop];
               presentBlock[s] = true;

           }
       }
    }
    return presentBlock;
}

        $(document).ready(function() {
            var rulesApplied= {};
            $('input').change(function() {
                current_cb = this;
                if ($(this).attr("checked")) {
                // toggle on

                    console.log("You ticked on " + current_cb.id);
                    combos = JSONSelect.match("." + current_cb.id, combinations);
                    rulesApplied[current_cb.id] = combos;
                    for(var key in combos) {
                        var obj = combos[key];
                        for(var prop in obj) {
                            var s = obj[prop];
                            $('#' + s).attr('disabled', 'disabled');

                            console.log("I disable " + obj[prop]);
                        }
                    }
                    console.log(rulesApplied);
                    return;
                }
                // toggle off
                console.log("You ticked off " + current_cb.id);
                combos = JSONSelect.match("." + current_cb.id, combinations);
                console.log(combos);
                delete rulesApplied[current_cb.id];
                console.log(rulesApplied);
                presentRules = createObjectsWithRules(rulesApplied);
                console.log(presentRules);

                for(var key in combos) {
                    var obj = combos[key];
                    for(var prop in obj) {
                        var s = obj[prop];
                        if (!presentRules[s]){
                          $('#' + s).removeAttr('disabled');
                          console.log("I enable " + obj[prop]);
                        }          
                    }
                }
                return;
            });
        });