How to apply multiple filters using $.grep()

Question

Hi guys i'm making a filter in a json object using $.grep() , the problem is that some times the filter is null and i have to test if the filter exists indeed. How can i make this code better in case of having more filters, thanks.

data.result = $.grep(this.Doutores, function (e, index) {
    if (data.descontos)
        return e.descontos == data.descontos;
});
data.result = $.grep(this.Doutores, function (e, index) {
    if (data.especialidade)
        return e.especialidade == data.especialidade;
});
data.result = $.grep(this.Doutores, function (e, index) {
    if (data.preco)
        return e.preco == data.preco;
});
data.result = $.grep(this.Doutores, function (e, index) {
    if (data.proftipo)
        return e.proftipo == data.proftipo;
});

Answer 1

I think a better code would be:

var filterBy = ['descontos', 'especialidade', 'preco', 'proftipo'];
var doutores = this.Doutores;
filterBy.forEach(function(filter){
    data.result = $.grep(doutores, function (e, index) {
        if (data[filter])
        {
            return e[filter] == data[filter];
        }
}

This way, you can add as many filters as you wish into the filterBy array and it will go through all the filters. You could also read about function composition - you can make all the filter functions into one "mega" filter and then filter the array only once (which will make your code more efficient).