javascript - Mongoose Promise 不将数据传递到下一个链

Question

我正在使用带有 Promise 的 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，当我操作结果并将其传递到下一个 .then() 链时，它无法访问。以下是完整功能。

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

而不是

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) 
  }
})

尝试

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:不要为每个函数使用多个返回值(如 forEach)。