NodeJ-等待異步方法的承諾解決。

Question

我編寫了一個驗證庫，希望能夠在Node中進行同步和異步調用。 我嘗試將諾言與async / co結合使用，但我無處可去。 有誰對如何使此代碼同步有很好的建議？ 我正在嘗試從驗證工廠中調用此函數，返回的查詢正在與數據庫異步傳遞。

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

我喜歡無禮。

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?
        });
    });
}

Answer 2

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);
    });
  });
}

用法示例：

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