写出一个程序，接受一个十六进制的数，输出该数值的十进制表示

语言：Js

代码：

const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;

void (async function () {
    // Write your code here
    while ((line = await readline())) {
        let str = line.substring(2).toUpperCase();
        let tokens = str.split('');
        let obj = {
            A: "10",
            B: "11",
            C: "12",
            D: "13",
            E: "14",
            F: "15",
            a: "10",
            b: "11",
            c: "12",
            d: "13",
            e: "14",
            f: "15",
        };
        let resultArr = [];
        tokens.forEach((item) => {
            Object.keys(obj).forEach((key) => {
                if (item === key) {
                    resultArr.push(obj[key]);
                }
            });
        });

        let sum = 0;
        resultArr.forEach((val, index) => {
            let newVal = val * Math.pow(16, index);
            sum += newVal;
        });
        console.log(sum);
    }
})();