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?
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
Actually you can create a closure instead of writing dozens of functions. Assuming asc_firstname_comparator
means "sort by x.firstname
",
function compareByProperty(field, order) {
return function (o1, o2) {
var retval;
if (o1[field] > o2[field])
retval = 1;
else if (o1[field] < o2[field])
retval = -1;
else
retval = 0;
if (order === "desc")
retval = -retval;
return retval;
}
}
...
myArray.sort(compareByProperty("firstname", "asc"));
I'd do something like this.
var comparators = {
asc_firstname_comparator : function(o1, o2){ ... }
desc_firstname_comparator : function(o1, o2){ ... }
};
Array.prototype.customSort(comparatorName) {
this.sort(comparators[comparatorName]);
}
var myArray = [ ... ]; // define array
myArray.customSort("asc_firstname_comparator");
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