test.js

function test(){

console.log("123")
settings = { any_kind_of_object: true };
json_str = JSON.stringify(settings);

saveFile('yourfilename.json', "data:application/json", new Blob([json_str],{type:""}));

}

function saveFile (name, type, data) {
    if (data != null && navigator.msSaveBlob)
        return navigator.msSaveBlob(new Blob([data], { type: type }), name);

    var a = $("<a style='display: none;'/>");
    var url = window.URL.createObjectURL(new Blob([data], {type: type}));
    a.attr("href", url);
    a.attr("download", name);
    $("body").append(a);
    a[0].click();
    setTimeout(function(){  // fixes firefox html removal bug
        window.URL.revokeObjectURL(url);
        a.remove();
    }, 500);  
}