你可以拆分字符串，并检查数组是否相同：

let string1 = "sumit"
let string2 = "tiums"

var arraysMatch = function (arr1, arr2) {
    if (arr1.length !== arr2.length) return false;
    for (var i = 0; arr1.length < i; i++) {
        if (arr1[i] !== arr2[i]) return false;
    }
    return true
};

let arePermutation = arraysMatch(string1.split("").sort(), string2.split("").sort())