maxSize is not correctly enforced

The implementation of this LRU cache does not enforce the documented behavior:

maxSize
Required
Type: number

The maximum number of items before evicting the least recently used items.

Running this code snippet produces true in the console:

const m = new QuickLRU({
    maxSize: 2
});
m.set("key1", "value1");
m.set("key2", "value2");
m.set("key3", "value3");
console.log(m.has("key1"));

The cache should only be able to store 2 items and when adding a total of 3 items to the list, the first key-value pair (key1-value1) should be evicted. However, from the result of executing the code, you can see that key1 is still in the cache.

[BTOdell]

It might be “expected behavior” if you’ve read the code and know that it’s going to behave that way. General users of this NPM package should only have to read the public documentation to understand what the package will do for them. If the implementation fails to produce the documented behavior then the implementation is bugged and should be fixed.

[adityapatadia]

@BTOdell it would be great if you can share your Map based LRU cache implementation. May be we can take inspiration and fix this one?