SOURCE

console.clear()
class LRUCache{
    constructor(length){
        this.length = length
        this.data = {}
    }

    set(key, value){
        if(this.data[key]){
            delete this.data[key]
        }
        this.data[key] = value
        const keys = Object.keys(this.data)
        if(keys.length > this.length){
            delete this.data[keys[0]]
        }
        console.log('set', this.data)
    }

    get(key){
        const value = this.data[key]
        delete this.data[key]
        this.data[key] = value
        console.log('get', this.data)
        return value
    }
}

var lru = new LRUCache(3)
lru.set(1,1)
lru.set(2,2)
lru.set(3,3)