Filter Example: All Social site(Facebook, Linkedin, VK etc ) filter way...

filter.js

var countries = [];
var methods = [];

$(document).ready(function(){
    function filter (){
        $(".wm-courses-popular-wrap").parent().hide();
        $(".wm-courses-popular-wrap").toArray().forEach((item) => {
            const hasCountry = countries.length > 0 ? countries.indexOf($(item).attr('country')) > -1 : true;
            const hasMethod = methods.length > 0 ? methods.indexOf($(item).attr('method')) > -1 : true;
            if (hasCountry && hasMethod) {
                $(item).parent().css('display', 'list-item');
            }
        })
    }
    $("#country li input").click(function(){
        var id = $(this).attr('id');
        if(id == "type1"){
            if($("#"+id).is(":checked")){
                for(var i=2; i<=197; i++){
                    $("#type"+i).prop('checked', true);
                    countries.push($("#type"+i).attr('id'));
                }
            }
            else {
                for(var i=2; i<=197; i++){
                    $("#type"+i).prop('checked', false);
                }
                countries = [];
            }
        }
        else {
            $("#type1").prop('checked', false);
            if($("#"+id).is(":checked")){
                countries.push(id);
            }
            else {
                countries.splice( countries.indexOf(id), 1 );
            }
        }
        filter()
    });
    $("#method li input").click(function(){
        var id = $(this).attr('id');
        if(id == "method1"){
            if($("#"+id).is(":checked")){
                for(var i=2; i<=6; i++){
                    $("#method"+i).prop('checked', true);
                    methods.push($("#method"+i).attr('id'));
                }
            }
            else {
                for(var i=2; i<=6; i++){
                    $("#method"+i).prop('checked', false);
                    methods = [];
                }
            }
        }
        else {
            $("#method1").prop('checked', false);
            if($("#"+id).is(":checked")){
                methods.push(id);
            }
            else {
                methods.splice( methods.indexOf(id), 1 );
            }
        }
        filter()
    });
});

this filter way is very optimized solution.

your code is very optimized and clean.