How to delete objects from array

Question

I want to remove object from array if they dont have a value

i have the API A, that returns to me this JSON:

{
  "code": 0,
  "data": [
    {
      "name": {
        "value": "Ana"
      },
      "fruit": {
        "value": "Grape"
      },
      "from": {
        "value": "BR"
      }
    },
    {
      "name": {
        "value": "Michael"
      },
      "fruit": {
        "value": "Apple"
      },
      "from": {
        "value": "US"
      }
    }
  ]
}

and with the API B, i can return the id for this user passing her the name

i have this code:

getData() {
  this.myService.getDataAPI_A()
    .subscribe((res) => {
      this.myList = res['data'];
      if (this.myList) {
        for (const key of this.myList) {
          this.getId(key.name.value);
        }
      }
    });
}

getId(name) {
  this.myService.getDataAPI_B(name) // api B returns id with the name
    .subscribe((res) => {
      this.myList.map((tempList) => {
        if (res.name === tempList.name.value) {
          tempList.userId = res.id; // creating a key and setting value
          return tempList;
        }
        return tempList;
      });
    });
}

then i got this json:

{
  "code": 0,
  "custodyBovespa": [
    {
      "name": {
        "value": "Ana"
      },
      "userId": "43",
      "fruit": {
        "value": "Grape"
      },
      "from": {
        "value": "BR"
      }
    },
    {
      "name": {
        "value": "Michael"
      },
      "fruit": {
        "value": "Apple"
      },
      "from": {
        "value": "US"
      }
    }
  ]
}

Michael does not existe in my data base, so the api returns to me null, and for some reason dont create the key in my json (why?). after this i want to remove the object that dont have userId how i can do this?

Rich · Accepted Answer · 2019-09-09 20:49:49Z

3

If you'd like your resultant array to contain only objects that contain the property userId, you can simply use plain JavaScript .filter.

In my below example, I am removing any element that does not have a "userId" prop.

var data = [
  {
    "name": {
      "value": "Ana"
    },
    "userId": "43",
    "fruit": {
      "value": "Grape"
    },
    "from": {
      "value": "BR"
    }
  },
  {
    "name": {
      "value": "Michael"
    },
    "fruit": {
      "value": "Apple"
    },
    "from": {
      "value": "US"
    }
  }
];
var dataFiltered = data.filter(val => val["userId"]);
console.log(dataFiltered);

answered Sep 9, 2019 at 20:49

Rich

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2 Comments

Igor Over a year ago

thx! i was trying here with .splice(), but was not able to remove from array

Patricio Vargas Over a year ago

Actually the best practice to do this will be doing it using rxjs. Time to start being more reactive, with reactive programming using RxJS. RxJS Also has a filter method,mergeMap concat map etc. Take a look to them

Md Rafee · Accepted Answer · 2019-09-09 21:11:00Z

As you said:

Michael does not existe in my data base

and the condition you set is

if (res.name === tempList.name.value) {
  tempList.userId = res.id; // creating a key and setting value
  return tempList;
}
return tempList;

As the your database doesn't have the the value 'Michael', The above condition is false. So, it gets out of the if clause and just return what it is without userId.

Now if you want to set the 'Michael' userId to null.

if (res.name === tempList.name.value) {
  tempList.userId = res.id; // creating a key and setting value
} else {
  tempList.userId = null;
}
return tempList;

Then filter out the data's using like @Rich answered.

console.log(data.filter(val => val['userId'] !== null);

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