Function filter

test/stringify.js:1260–1262

(prefix, value)

    t.test('strictNullHandling works with custom filter', function (st) {
        var filter = function (prefix, value) {
            return value;
        };

        var options = { strictNullHandling: true, filter: filter };
        st.equal(qs.stringify({ key: null }, options), 'key');