Mongoose Promise 不会将数据传递到下一个链

Question

我正在使用 mongoose 查询 MongoDB。结果只能在第一个.then(function(results){ // can send the result from here..}) 中访问。但是当我操纵结果并将其传递给下一个.then()chain 时，它是不可访问的。下面是完整的功能。

exports.getAcl = function(req, res) {

  User.findAsync({}, {
    acl: 1
  })
  .then(function(results){
    var aclList = [];
    results.forEach(function(result,index,arr){
      aclList[result._id] = result;
      if (index === (arr.length - 1)) {
        console.log('I can log the aclList here..', aclList)
        return aclList // But neither able to send it to next chain nor to front end res.send(aclList) 
      }
    })
  })
  .then(function(aclList){
    console.log(aclList) // Loging undefined
    res.status(200).json(aclList); // undefined
  })
  .catch(handleError(res));
}

请让我知道我在这里做错了什么......谢谢

Answer 1

代替

results.forEach(function(result,index,arr){
  aclList[result._id] = result;
  if (index === (arr.length - 1)) {
    console.log('I can log the aclList here..', aclList)
    return aclList // But neither able to send it to next chain nor to front end res.send(aclList) 
  }
})

试试

var resArray = [];
results.forEach(function(result,index){
  aclList[result._id] = result;
  if (index === (arr.length - 1)) {
    newRes.push(aclList);
  }
})
// console.log(resArray) to verify they are there
return resArray;

底线：不要对每个函数使用多个返回（如forEach）。