NodeJs -等待异步方法的承诺解析

Question

我已经编写了一个验证库，我希望能够在Node中同步和异步调用它。我曾尝试使用async/co的承诺，但我哪儿也去不了。有没有人有一个好的建议，如何能够使这个代码同步?我试图从验证工厂调用这个，并且返回的查找正在异步地到达数据库。

var lookupFactory = require('../lookup/lookupFactory');
var Promise = require("bluebird");
var async = require('async');
exports.validate = function (required, field, errors) {
    if (required && field.value == null) {
        errors.push('Field is required');
       return;
   }
    var lookupType = field.validation.lookupType;
    var s = lookupFactory.lookup(lookupType);
    s.validate('12', function (err, data) {
        if (data.length != 1) {
            errors.push('Field value is not valid');
        }
    });
};

Answer 1

exports.validate = function (required, field) {
  var lookupType = field.validation.lookupType;
  var s = lookupFactory.lookup(lookupType);
  return new Promise(function(resolve, reject) {
    if (required && field.value == null) {
      return reject('Field is required');
    }
    s.validate('12', function (err, data) {
      if(err) {
        return reject(err);
      } else if (data.length != 1) {
        return reject('Field value is not valid');
      }
      resolve(data);
    });
  });
}

使用例子:

validate(true, 'name')
  .then(function(data) { console.log('Validation succeeded:', data); },
        function(reason) { console.log('Validation failed:', reason); });

Answer 2

我喜欢承诺。

exports.validate = function (required, field, errors) {
    return new Promise(function(fulfill) {
        if (required && field.value == null) {
            errors.push('Field is required');
            return;
        }
        var lookupType = field.validation.lookupType;
        var s = lookupFactory.lookup(lookupType);
        s.validate('12', function (err, data) {
            if (data.length != 1) {
                errors.push('Field value is not valid');
            }
            fulfill(null /*Argument passed to the other function*/); //Is it here the code end?
        });
    });
}