Memo_cache using a Map

memo.js

const cache = new Map();

///
function memo() {
    let deleteAfterUse = true; // enable cache deletion after use by default
    let maxKeys = 32;
    
    const memoFunc = function (value=null) {
        const size = cache.size;
        if (value) {
            if (size >= maxKeys) {
                cache.delete(cache.keys().next().value);
            }
            const key = (size + 1).toString();
            const result = JSON.stringify(value);
            cache.set(key, result);
            return;
        }

        if (size > 0) {
            const randomKey = Array.from(cache.keys())[Math.floor(Math.random() * size)];
            const result = cache.get(randomKey);
            if (deleteAfterUse) {
                cache.delete(randomKey);
            }
            return JSON.parse(result);
        }

        return null;
    };

    memoFunc.fetchByKey = (key) => {
        if (cache.has(key)) {
            const result = cache.get(key);
            if (deleteAfterUse) {
                cache.delete(key);
            }
            return JSON.parse(result);
        }
        return null;
    };

    memoFunc.setDeleteAfterUse = (deleteCache = true) => {
        deleteAfterUse = deleteCache;
    };

    memoFunc.setMaxKeys = (MaxKeys = 32) => {
        if(MaxKeys>0){
            maxKeys = MaxKeys;
        }
    };
    
    return memoFunc;
}

const myMemo = memo();
myMemo.setMaxKeys(32);

myMemo("value1");
myMemo("value2");
myMemo("value3");



console.log(myMemo.fetchByKey("1"));

myMemo.setDeleteAfterUse(false);
console.log(myMemo()); 
console.log(myMemo()); 
console.log(myMemo()); 

myMemo.setDeleteAfterUse(true);
console.log(myMemo()); 
console.log(myMemo());
console.log(myMemo());//empty