实现一个LRU缓存函数

[DamomHd]

• 通过Map实现

function LRUCache (length){
    this.cacheMap = new  Map();
    this.length = length;

}
LRUCache.prototype.get(key){
    if(this.cacheMap.has(key)){
        // 命中 取值 修改顺序
        let temp = this.cacheMap.get(key);
        this.cacheMap.delete(key)
        this.cacheMap.set(key,temp)
        return temp
    }
    return -1
}

LRUCache.prototype.put(key,val){
    if(this.cacheMap.has(key)){
        this.cacheMap.delete(key)
        this.cacheMap.set(key,val)
    }
    else{
        // 堆超出最大数
        if(this.cacheMap.size >= this.length){
            let firstKey = this.cacheMap.keys().next.value;
            this.cacheMap.delete(firstKey)
            this.cacheMap.set(key,val)
        }
        else{
             this.cacheMap.set(key,val)
        }
    }

}