Question

创建并保存模型记录

我的代码：

var mongoose= require('mongoose');
mongoose.connect("****");

var db = mongoose.connection;
db.on(‘error’, console.error.bind(console, 'connection error:'));

var personSchema = new mongoose.Schema({
    name : String,
    age : Number,
    favoriteFoods :[String]
});

var Person = mongoose.model(‘Person’, personSchema);

var createAndSavePerson = function(done) {
 var mr = new Person({
    name: 'Mrdude',
    age: 22,
    favoriteFoods: ['Ice Creame', 'Grills']})

  mr.save(function(err, mr) {
    if(err) return console.error(err);
  });
  done(null, mr);
};

我找不到此错误

我收到“无法读取null的属性'名称'”错误

请指出我错了

Answer 1

您需要添加以下行：

function Step({ number, status="NOT_DONE" }) {
  switch (status) {
    case "DONE":
      return <div className="done"><i className="fas fa-check"/></div>
    case "CURRENT":
      return <div className="active">{number}</div>
    case "NOT_DONE":
    default:
      return <div className="not-done">{number}</div>
  }
}

function ProgressBar({ numberOfSteps = 0, currentStep = 0 }) {
  if (!numberOfSteps) return null;

  const steps = [];
  for (let i = 0; i < numberOfSteps; i++) {
    const status = i < currentStep ? 'DONE' : i === currentStep ? 'CURRENT' : 'NOT_DONE';
    steps.push(<Step number={i} status={status} />)
  }

  return (
    <div>
      {steps}
    </div>
  )
}

Answer 2

var mongoose= require('mongoose');
mongoose.connect("****");

var db = mongoose.connection;
db.on(‘error’, console.error.bind(console, 'connection error:'));

var personSchema = new mongoose.Schema({
name : String,
age : Number,
favoriteFoods :[String]
});

var Person = mongoose.model(‘Person’, personSchema);

var createAndSavePerson = function(done) {
var mr = new Person({
name: 'Mrdude',
age: 22,
favoriteFoods: ['Ice Creame', 'Grills']})

mr.save(function(err,data) {
if(err)
  {
    done(err);
  }
else
{
    done(null, data);
}
});

};

现在工作正常，我在回调函数中犯了一个错误，因此无法访问属性。我返回的是不正确的“先生”。

Answer 3

您将回调函数放置在错误的位置。

您的done是回调函数，传递给createAndSavePerson，因此save完成时应调用它。

var mongoose= require('mongoose');
mongoose.connect("****");

var db = mongoose.connection;
db.on(‘error’, console.error.bind(console, 'connection error:'));

var personSchema = new mongoose.Schema({
    name : String,
    age : Number,
    favoriteFoods :[String]
});

var Person = mongoose.model(‘Person’, personSchema);

var createAndSavePerson = function(done) {
 var mr = new Person({
    name: 'Mrdude',
    age: 22,
    favoriteFoods: ['Ice Creame', 'Grills']})

  mr.save(function(err, mr) {
    return done(err, mr);
  });

  // Wrong position
  // done(null, mr); 
};


// Call function when you need
createAndSave((err, data) => {
  if (err) console.log(err);
  else console.log(data);
})

使用节点将文档保存在mongo中

3 个答案: