[프로그래머스/javascript] 할인행사

function solution(want, number, discount) {
    var answer = 0;
    const items = {}
    for(let i=0;i<want.length;i++){
        items[want[i]]=number[i]
    }
    for(let i=0;i<=discount.length-9;i++){
        let itemsCopy = Object.assign({},items)
        for(let j=i;j<i+10;j++){
            if(itemsCopy[discount[j]]){
                itemsCopy[discount[j]]--
            }
            if(itemsCopy[discount[j]]===0){
                delete itemsCopy[discount[j]]
            }
        }
        if(Object.keys(itemsCopy).length===0) answer++
    }
    return answer;
}