检查之前是否已经存在字段以在 MongoDB / NodeJS 上创建文档

Question

I'm using NodeJS with Mongoose .

    const payload = { 
        id,
        email,
        password: md5(password)
    }
    User.create(payload, async(error, result) => {
        // DO SOMETHING
    })

I'm looking the best way to check if id and email doesn't already exists before to create a new document on my collection.

Answer 1

You have to make a call first on the DB to check for the email.

The actual code in nodejs would look something like this:

mongo.connect(url, {
  useNewUrlParser: true,
  useUnifiedTopology: true
}, async (err, client) => {
  if (err) {
   console.error(err);
   return;
  }
  db = client.db('a_db');
  const payload = { 
    id: 'some_id',
    email: 'some_email@email.com',
    password: md5('password')
   }
   db.collection('users').findOne({email: payload.email}, (err, buffer) => {
      buffer.toArray((err, res) => {
         if (res) console.log('user already in')
         else{
           db.collection('users').insertOne(payload, (err, res) => {
              // DO SOMETHING
           });
         }
      });
   });
});

On the other hand you should never use md5 for hashing your passwords because it has being broken. You should us at least sha512.