Extend Backgrid ClientSideFilter with a pick filter, to pre-filter data set. Useful to combine text search with a select, checkboxes or radio buttons filters.

Backgrid.ClientSideFilterWithPickFilter

// Subclass Backgrid Filter to pass an extra 'pick' filter
Backgrid.ClientSideFilterWithPickFilter = Backgrid.Extension.ClientSideFilter.extend({
    pickFilter: null,
    setPickFilter: function (attrs) {
        this.pickFilter = attrs;
        this.search();
        return this;
    },
    makeMatcher: function (query) {
        var regexp = this.makeRegExp(query);
        return function (model) {
            var json = model.toJSON();

            // Test the pick filter (if set)
            if (this.pickFilter) {
                var match = _.find(this.pickFilter, function (value, key) {
                    return json[key] === value;
                });
                if (match === undefined) return false;
            }

            // Test the search filter
            var keys = this.fields || model.keys();
            for (var i = 0, l = keys.length; i < l; i++) {
                if (regexp.test(json[keys[i]] + "")) return true;
            }
            return false;
        };
    }
});
    
// Assuming you have a checkbox to only show rows with Valid=true
var filter = new Backgrid.ClientSideFilterWithPickFilter({...});
$('input[name=valid]').change(function(e) {
	filter.setPickFilter(e.target.checked ? {Valid: true} : null);
});

Charlie Irish asked me for a way to combine Backgrid Select Filter with Backgrid Filter. They were written to be standalone so hard to do. However, Backgrid.ClientSideFilter can be extended with a pick filter, to pre-filter data. You can then bind input or select elements to narrow down the rows, prior to the text search.