如何解决 promiss.all() 并想删除一个级别的对象

Question

我想合并两个sequelize数据的结果。所以我只是创建了两个模型的实例，然后立即使用 promise.All() 解析它们。我做了以下事情来达到同样的目的：

let screensP = AppEvent.findAll({
        attributes : [
            'id',
            'title'
        ],
    });
let eventsP = AppScreen.findAll({
        attributes : [
            'id',
            'title'
        ],
    });
exports.settings = function(req, res, next){
    Promise.all([{'screens' : screensP, 'events' : eventsP}])
    .then((values) => {
        res.json({
            'status': 200,
            'data': values,
        });
    });
}

但响应包含如下所示的承诺对象

{
    "status": 500,
    "data": [
        {
            "screens": {
                "isFulfilled": true,
                "isRejected": false,
                "fulfillmentValue": [
                    {
                        "id": 1,
                        "title": "click"
                    },
                    {
                        "id": 2,
                        "title": "comment"
                    }
                ]
            },
            "events": {
                "isFulfilled": true,
                "isRejected": false,
                "fulfillmentValue": []
            }
        }
    ]
}

我想要这样的结果

{
    "status": 200,
    
    "events": [
        {
            "id": 1,
            "title": "dashboard"
        },
        {
            "id": 2,
            "title": "profile"
        },
        {
            "id": 3,
            "title": "book"
        }
    ],
    
    "screens": []
}

我应该怎么做才能得到上面的回复？

Answer 1

    res.json({
        'status': 200,
        ...values,
    });

Answer 2

对于 Promise.all() 的调用，您传入一个数组，其中包含一个元素，该元素是一个具有两个属性的对象，每个属性都是一个承诺。这就是您在结果中看到的（isFulfilled 和其他属性）。要解析 promise，您需要传入一个 promise 数组，而不是一个对象。

此示例使用更易于阅读的 async/await。

exports.settings = async function(req, res) {
  // you can deconstruct the returned elements when the promise is resolved
  const [ screens, events ] = await Promise.all([
    // returns a promise that will resolve "events"
    AppEvent.findAll({
      attributes : [
          'id',
          'title'
      ],
      // if you don't need to parse to Instance objects, adding raw:true will be faster
      // raw: true,
    }),
    // returns a promise that will resolve "screens"
    AppScreen.findAll({
      attributes : [
          'id',
          'title'
      ],
      // if you don't need to parse to Instance objects, adding raw:true will be faster
    })
  ]);

  // return the results
  return res.json({
    'status': 200,
    'data': {
      screens,
      events
    },
  });
};

使用 thenables 的相同示例：

exports.settings = function(req, res) {
  // you can deconstruct the returned elements when the promise is resolved
  return Promise.all([
    // returns a promise that will resolve "events"
    AppEvent.findAll({
      attributes : [
          'id',
          'title'
      ],
    }),
    // returns a promise that will resolve "screens"
    AppScreen.findAll({
      attributes : [
          'id',
          'title'
      ],
    })
  ])
  .then(([ screens, events ]) => {
    // return the results
    return res.json({
      'status': 200,
      'data': {
        screens,
        events
      },
    });
  });
};

如何解决 promiss.all() 并想删除一个级别的对象

How to resolve promiss.all() and want to remove a level of object

node.js

promise

express

sequelize.js