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 tokens = parseInt(line,16);
        console.log(tokens);
    }
}()

我的方法

Number()函数也差不多的用法。

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()){
        console.log (eval(line) )
    }
}()

会碎觉的熊猫——的方法

eval()

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 map = new Map()
        for(let i = 0; i < 10; i++){
            map.set(String(i), i)//注意：这里的String()中的S大写，是String()函数，String() 函数把对象的值转换为字符串。
        }
        map.set('A', 10).set('B', 11).set('C', 12).set('D', 13).set('E', 14).set('F', 15)//连续set多个值
        let str = line.substring(2, line.length)//16进制的前缀是0x,数字零和英文字母X
        let arr = str.toUpperCase().split('')//输入的字母不一定全是大写字母，需要转大小写

        let result = 0
        for(let i = 0; i < arr.length; i++){
            let tempNum = Math.pow(16, arr.length - i - 1)//pow(x,y) 方法返回 x 的 y 次幂。
            result += map.get(arr[i]) * tempNum
        }
        console.log(result)
    }
}()

牛客944083017号——的方法

substring()

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 arr = line.split("0x")[1].split("").reverse();
        let total = 0;
        let str1 = ["a", "b", "c", "d", "e", "f"];
        let str2 = ["A", "B", "C", "D", "E", "F"];
        arr.forEach((item, index) => {
            let num =
                str1.indexOf(item) != -1
                    ? str1.indexOf(item) + 10
                    : str2.indexOf(item) != -1
                    ? str2.indexOf(item) + 10
                    : parseInt(item);//太会用三目运算符了吧！！！
            while (index > 0) {
                num = num * 16;
                index--;
            }
            total = total + num;
        });
        console.log(total);
    }
}()

｛&｝——的方法