service - sails.js 使用查找查询时，服务返回对象未定义

Question

我创建了一个名为 AppService 的服务。它的函数 getUserPostionOptions 应该返回一个对象:

getUserPostionOptions: function (user) {
   // PositionOptions.findOne({id:'53f218deed17760200778cfe'}).exec(function (err, positionOptions) {
        var positionDirectionsOptions = [1,2,3];
        var positionLengthsOptions = [4,5,6];
        var object = {
            directions:positionDirectionsOptions, 
            lengths:positionLengthsOptions
        };   
        return object;
  // });
}

这有效，在我的 Controller 中，positionOptions 被正确填充:

var positionOptions = AppService.getUserPostionOptions(user);

但是，当我取消注释查找查询时，找到了该项目，但对象返回未定义。

提前感谢您的帮助

Answer 1

SailsJs ORM(以及几乎 NodeJs 数据库查询方法)通过回调函数使用非阻塞机制。所以你必须将代码更改为:

getUserPostionOptions: function (user, callback) {
  PositionOptions.findOne({id:'53f218deed17760200778cfe'}).exec(function (err, positionOptions) {
    var positionDirectionsOptions = [1,2,3];
    var positionLengthsOptions = [4,5,6];
    var object = {
        directions:positionDirectionsOptions, 
        lengths:positionLengthsOptions
    };   
    callback(null, object); // null indicates that your method has no error
  });
}

然后使用它:

AppService.getUserPostionOptions(user, function(err, options) {
  if (!err) {
    sails.log.info("Here is your received data:");
    sails.log.info(options);
  }
});