title: How to add within an array information using findOneAndUpdate without deleting information that was previously contained
body: <p>does anyone know how I can add an object to an array called worker_info without "replacing" all the information it contains? (I'm learning the mean stack) I have this code but what it does is replace all the information and erase the other data I already had. With the code I got this, summarizing what I want is that the worker_info array be added the worker object without deleting the rest, I would appreciate if someone can help me, any advice would be useful, thank you</p>
  
  <p>I tried this</p>
  
  <pre><code> User.findOneAndUpdate(serviceId, { "$push": { services: { worker_info: worker } } }, { new: true }, (err, us) =&gt; {
  
  res.status(200).send(us);
                      });
  </code></pre>
  
  <p>I expected something like this</p>
  
  <pre><code>{
      "services": [
          {
              "worker_info": [],
              "_id": "5ce485a3288efe1834d4d71c",
              "user_address": "dbarva252",
              "description_service": "descripcion servicio",
              "skill_type": "wasting time",
              "amount_money": 0
          },
          {
              "worker_info": [{
                  "_id": "5ce4867e288efe1834d4d71e",
                  "name": "Trabajador",
                  "surname": "arreglador",
                  "identification": "123457669",
                  "birthdate": "1 febrero 1999",
                  "skills": "time waster fixer",
                  "image": null,
                  "__v": 0
              }],
              "_id": "5ce485c5288efe1834d4d71d",
              "user_address": "esta es una direccion",
              "description_service": "descripcion servicio 2",
              "skill_type": "wasting time part 2",
              "amount_money": 0
          }
      ],
      "_id": "5ce48569288efe1834d4d71a",
      "user": "usuario123",
      "name": "mauricio",
      "surname": "barva",
      "identification": "123123",
      "birthdate": "6 febrero 2000",
      "city": "city",
      "address": "tv 1d norte",
      "cellphone": "123",
      "image": null,
      "status": false,
      "__v": 0
  }
  </code></pre>
  
  <p>but I got this</p>
  
  <pre><code>{
      "services": [
          {
              "worker_info": [],
              "_id": "5ce485a3288efe1834d4d71c",
              "user_address": "dbarva252",
              "description_service": "descripcion servicio",
              "skill_type": "wasting time",
              "amount_money": 0
          },
          {
              "worker_info": {
                  "_id": "5ce4867e288efe1834d4d71e",
                  "name": "Trabajador",
                  "surname": "arreglador",
                  "identification": "123457669",
                  "birthdate": "1 febrero 1999",
                  "skills": "time waster fixer",
                  "image": null,
                  "__v": 0
              }
          }
      ],
      "_id": "5ce48569288efe1834d4d71a",
      "user": "usuario123",
      "name": "mauricio",
      "surname": "barva",
      "identification": "123123",
      "birthdate": "6 febrero 2000",
      "city": "city",
      "address": "tv 1d norte",
      "cellphone": "123",
      "image": null,
      "status": false,
      "__v": 0
  }
  </code></pre>
  
  <p>As you can see, it replaces all the information.</p>