Question

在我的下面的代码中，onResolve（）函数在第一个函数之前调用，然后在其他函数之前调用（在req.body.length＆gt; 1时看到它）。知道为什么吗？我想将保存的资产列表添加到数组中，然后在所有findOneAndUpdate执行完成后在响应中发送该数组。

exports.saveAssetLists = function(req, res) {
  console.log('starting save asset lists');
  if (!Common.testIfValidForSave(req.body, true)) {
    res.status(400).send({error:'Invalid request body: ' + JSON.stringify(req)});
    return;
  }

  var deferred = null;
  var savedAssetLists = [];
  for (var i = 0; i < req.body.length; i++) {
    var newAssetList = new AssetList(req.body);
    var d = AssetList.findOneAndUpdate({_id: newAssetList._id }, newAssetList, {upsert:true, new:true}).exec().then(function(obj) {
      console.log('then - obj: ' + JSON.stringify(obj));
        savedAssetLists.push(obj);
    });
    if (!deferred) {
      deferred = d;
    } else {
      deferred.chain(d);
    }
  }
  deferred.onResolve(function(err, result) {
    console.log('onResolve - err: ' + err + ', result: ' + result + ', savedAssetLists: ' + savedAssetLists);
    res.send({data: savedAssetLists});
  })
  .onReject(function(err) {
    res.status(500).send({error: err});
  });
  return deferred;
};

这是日志输出：

starting save asset lists
then - obj: {"_id":"561eafe95c0df2c0468cb798","name":"Asset List 1","__v":0,"assets":[null]}
onResolve - err: null, result: undefined, savedAssetLists: { _id: 561eafe95c0df2c0468cb798,
  name: 'Asset List 1',
  __v: 0,
  assets: [ null ] }
then - obj: {"_id":"561eafe95c0df2c0468cb799","name":"Asset List 2","__v":0,"assets":[null]}

根据Vsevolod的建议，我将代码更改为以下内容，但是后来的方法永远不会被调用：

exports.saveAssetLists = function(req, res) {
  console.log('starting save asset lists');
  if (!Common.testIfValidForSave(req.body, true)) {
    res.status(400).send({error:'Invalid request body: ' + JSON.stringify(req)});
    return;
  }

  var promises = [];
  var savedAssetLists = [];
  for (var i = 0; i < req.body.length; i++) {
    var newAssetList = new AssetList(req.body[i]);
    var p = AssetList.findOneAndUpdate({_id: newAssetList._id }, newAssetList, {upsert:true, new:true}).exec();
    promises.push(p);

  }
  Promise.all(promises).then(function(values) {
    console.log('onResolve - err: ' + err + ', values: ' + values + ', savedAssetLists: ' + savedAssetLists);
    res.send({data: values });
  }, function(err) {
    res.status(500).send({error: err});
  });
};

Answer 1

您可以做的是从req.body创建一系列承诺：

var promises = req.body.map(function(data){
    var newAssetList = new AssetList(data);
    return AssetList.findOneAndUpdate({_id: newAssetList._id }, newAssetList, {upsert:true, new:true})
});

Promise.all(promises).then(function(results){
   return res.send({data: results});
}).catch(function(err){
    return res.status(500).send({error: err});
});

小注意：代码中不需要mpromise库。这应该适用于猫鼬4 +

在此之前调用mongoose mpromise onResolve

1 个答案: