const test = {
self: this,
a: 1,
b: 2,
list: [],
add: function(item){
    //add element to list
    self.list.push(item);
},
addWithDelay: function(item, delay){
    //add element to list with delay
    setTimeout(()=>{
        this.list.push(item);
    }, delay);
},
remove: function(i){
    //delete element #i from list
    this.list = this.list.slice(1,i);
},
modify: function(c){
    //modify parameters
    a = b + c;
}
};