我如何在对象中保存这些函数，循环遍历所有函数并将它们放在我的storeobject中

var fn1 = function1();
var fn2 = function2();
var fn3 = function3();
var fn4 = function4();

const store = {
    storeId : 1,
    cache:{},
    add:function(fn){
        if(!fn.id){
            fn.id = this.storeId++;
            this.cache[fn.id] = fn;
            return true;
        }
    }
}

for(let i = 0;i < 4;i++){
    store.add ?; // i got stuck here what i should i do in order to store my functions using the for loop
}