Arr008-判断两数组是否相等

function isEqual(arr1, arr2) {
    if(arr1.length !== arr2.length) {
        return false;

    }
    const countMap1 = count(arr1);
    const countMap2 = count(arr2);

    function count(arr = []) {
        const resMap = new Map();
        for(const item of arr) {
            resMap.set(item, (resMap.get(item) || 0) + 1 );
        }
        return resMap;
    }

    for(const [key,count] of countMap1) {
        if(countMap2.get(key) !== count) {
            return false;
        }
    }

    return true
}