An example for an object to remove the item where the value is null or " ".
var queryjson = require('queryjson');
const param = {
userName:'11',
password:'11',
email:'11',
tel:'1',
userType:''
};
const cc = queryjson.queryjson(param);
// cc = {
userName:'11',
password:'11',
email:'11',
tel:'1'
}
const dd = queryjson.queryjsontostring(param)
// dd = 'userName=11&password=11&email=11&tel=1'