Question

I’m sorting array:

myArray.sort(comparators.some_comparator);

and I have several comparator to choose from:

comparators = {

   asc_firstname_comparator : function(o1, o2){
    ...
   }

   desc_firstname_comparator : function(o1, o2){
    ...
   }

   etc...
}

I want to write function which returns certain comparator depending on input data. It should figure out comparator from string inputs, something like this:

function chooseComparator(field, order){

  return "comparators."+order+"_"+field+"_comparator";

}

So is it possible to pass only function name string to sort() method or I’ll need to pass reference to correct comparator somehow?

Answer 1

use the subscript notation for indexing the javascript object (obj.prop is the same as obj["prop"], but the latter way you can create property names dynamically):

function chooseComparator(field, order){ 

  return comparators[order+"_"+field+"_comparator"]; 

}

and yes, you have to pass a function object to the sort() function, just a name is not enough