用javascript编写简单银行取钱存钱流程（函数）

 const readline = require('readline-sync')//引用readline-sync
 let arr = [['zhang', '', ], ['yang', '', ]];
 //登陆
 let add = function () {
     let s = ;//输入错误的次数
     while (true) {
         console.log('请输入用户名：');
         let user = readline.question();
         console.log('请输入密码：');
         let password = readline.question();
         for (let i = ; i < arr.length; i++) {
             if (user === arr[i][] && password === arr[i][]) {
                 console.log('欢迎你，登陆成功');
                 mean(i);
                 return;
             }
         }
         //输入不正确，超过三次
         if (s != ) {
             console.log(`密码或账户有误，你还有${s}次机会，请重新输入！`);
             s--;

         } else {
             console.log('对不起，账户锁定！');
             break;
         }
     }
 }
 //存款
 let fn1 = function (i) {

     console.log('存款');
     console.log('请输入存款金额：');
     let cunkuan = readline.question() - ;
     arr[i][]+= cunkuan;
     console.log('系统正在为你存钱请稍等。。。。。\n存钱成功您当前余额为' + arr[i][]);
 }
 //取款
 let fn2 = function (i) {
     console.log('取款');
     console.log('请输入取款金额：');
     let qukuan = readline.question() - ;
     if (qukuan > arr[i][]) {
         console.log('对不起你的余额不足！，请重新输入金额或者退出');
     } else {
         arr[i][] = arr[i][] - qukuan;
         console.log('正在为你取钱。。。。。\n您当前余额为：' + arr[i][]);
     }
 }
 //查看
 let fn3 = function (i) {
     console.log('查看');
     console.log('正在查询。。。。\n您当前的余额为：' + arr[i][]);
 }

 //退出

 let fn4 = function () {
     console.log('退出');
     console.log('欢迎你下次使用！');
 }

 //流程
 let mean = function (i) {
     for (let yewu = ; yewu >= ; yewu++) {
         console.log('请选择业务：\n1.存款： \n2.取款： \n3.查看： \n4.退出：');
         let yewu = readline.question() - ;
         switch (yewu) {
             case :
                 fn1(i);
                 continue;
             case :
                 fn2(i);
                 continue;
             case :
                 fn3(i);
                 continue;
             case :
                 fn4();
                 return;
         }break;
     }
 }
 add();