在underscore.js _.where中使用变量

Question

is it possible to use variables with .where in _.js?

I am making a filtering system that gets an array of objects and filters out the selected objects on click. However, the objects to be filtered are different based on the elements chosen, so I would like to use _.js to filter variables passed to it with _.where

Hardcoded values work perfectly, but when replaced with replica variables, it shoots out a blank array.

var user_filters = user_array;
var filtered_text;
$('.allFilters li').click(function () {
    var $this = $(this); 
    var selected_filter = $this.siblings('a').text();
    selected_filter = selected_filter.toLowerCase();
    var filters = $this.attr('data-filter-value');
    filters = '"'+filters+'"';
    selected_filter = selected_filter;
    console.log(selected_filter, filters);
    user_filters = _.where(user_filters, {selected_filter: filters});
    console.log (user_filters);
});

Answer 1

There is a way to use variables when calling where , which is to create an object literal which where expects. This can be done using the underscore function _.object which can take either an array of keys and an array of values or an array of key value pairs.

In your example you could have done:

user_filters = _.where(user_filters, _.object([[selectedFilter, filters]]));

Answer 2

I think you're looking for something like this:

user_filters = user_filters.filter(function(item) {
  return item[selected_filter] === filters;
});

(and leave out the filters = '"'+filters+'"'; line)

Or, using Underscore's filter :

user_filters = _.filter(user_filters, function(item) {
  return item[selected_filter] === filters;
});

Answer 3

Variables can be used if surrounded them by square brackets:

In your case you can do this:

var selected_filter = $this.siblings('a').text();
    selected_filter = selected_filter.toLowerCase();

_.where(user_filters, {[selected_filter]: filters});