我在自定义验证中在猫鼬校准中遇到问题

Question

我正在使用express-validator，并且使用mongoose数据库find进行了一个自定义验证，现在我无法发送withMessage。这是我的代码，尽管进程在Error处停止，但是在Json中不显示消息，但是在用户创建时显示全部。

        body('mobile', 'Mobile number is required')
          .custom((value, {req, loc, path}) => {
            User.countDocuments({mobile: value}, function (err, c) {
              if (err) {
                console.log('An error happen in db')
              }
              if (c > 0) {
                throw new Error('Mobile already  exists finally')
              } else {
                return value
              }
            })
            return value
          })
          .withMessage('Mobile already exists'),

以下是控制台的日志

functions: Beginning execution of "app"
>  events.js:298
>        throw er; // Unhandled 'error' event
>        ^
>
>  Error: Mobile already  exists finally
>      at /Users/kamal/Documents/personal/asghar/codes/functions/app/controllers/users_controller.js:117:23
>      at /Users/kamal/Documents/personal/asghar/codes/functions/node_modules/mongoose/lib/model.js:4849:16
>      at /Users/kamal/Documents/personal/asghar/codes/functions/node_modules/mongoose/lib/model.js:4849:16
>      at /Users/kamal/Documents/personal/asghar/codes/functions/node_modules/mongoose/lib/helpers/promiseOrCallback.js:24:16
>      at /Users/kamal/Documents/personal/asghar/codes/functions/node_modules/mongoose/lib/model.js:4872:21
>      at /Users/kamal/Documents/personal/asghar/codes/functions/node_modules/mongoose/lib/query.js:4379:11
>      at /Users/kamal/Documents/personal/asghar/codes/functions/node_modules/kareem/index.js:135:16
>      at processTicksAndRejections (internal/process/task_queues.js:79:11)
>  Emitted 'error' event on Function instance at:
>      at /Users/kamal/Documents/personal/asghar/codes/functions/node_modules/mongoose/lib/model.js:4851:13
>      at /Users/kamal/Documents/personal/asghar/codes/functions/node_modules/mongoose/lib/helpers/promiseOrCallback.js:24:16
>      [... lines matching original stack trace ...]

我需要添加，如果条件接近return value，但问题是在这里回调并没有带给我c的值，在上面它是正确的，甚至由于错误引发而停止，但是我不想引发错误想进一步withMessage('Mobile already exists')我肯定在回调中做错了。请提出解决方法

Answer 1

这应该工作

body("mobile").custom(value => {
    return User.countDocuments({ mobile: value })
        .then(count => {
            if (count > 0) return Promise.reject("Mobile Number already Exists");
        })
        .catch(error => console.error(error.message));
});