Find object value in array of objects JavaScript

Question

I want to check if a object value exist in a array of objects with "some".

I only can find that the object hobbys exist in the array with "some"

"users": [
   {
     "type": "User",
     "name": "Sarah",
     "hobbys":
      {
        first: "something1",
        second: "something2"
      }
   }
]

users.some(item => item.hobbys); // true

I want to check if "first" value in "hobbys" exist.

@DennisVash That will throw if user.hobbies does not exist — CertainPerformance
– CertainPerformance, Commented May 10, 2019 at 9:22
@CertainPerformance users.some(user => user.hobbies && user.hobbies.first); ;-) — Dennis Vash
– Dennis Vash, Commented May 10, 2019 at 9:25

CertainPerformance · Accepted Answer · 2019-05-10 09:08:58Z

1

Check if the hobbys is an object and has an own property of first:

const users = [{
  "type": "User",
  "name": "Sarah",
  "hobbys": {
    first: "something1",
    second: "something2"
  }
}];

const userWithFirstHobbyExists = users.some(({ hobbys }) => (
 typeof hobbys === 'object' && hobbys.hasOwnProperty('first')
));
console.log(userWithFirstHobbyExists);

answered May 10, 2019 at 9:08

CertainPerformance

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3 Comments

Yevhen Horbunkov Over a year ago

To me hasOwnProperty() is a tool for tracking down the inheritance, which is muuuuch slower than simple users.some(item => item.hobbys.first != undefined || false). What's the benefit of using hasOwnProperty() here?

CertainPerformance Over a year ago

hasOwnProperty is the way to check to see if the property exists on the object: != undefined will also evaluate to false if the property does exist, but its value is undefined. It's an edge case, but from OP's question, it's not clear if it's something to worry about or not. If he also wants to exclude first values of undefined, then you're right, check !== undefined

Yevhen Horbunkov Over a year ago

The question body states "want to check if "first" value in "hobbys" exist", so regardless of the first value, hasOwnProperty() seems to be massive overkill.

Nikhil Aggarwal · Accepted Answer · 2019-05-10 09:12:50Z

1

You can try following assuming hobbys will always be an object and first will not have any falsy values.

let users = [{"type": "User","name": "Sarah","hobbys": {"first": "something1","second": "something2"}}];

console.log(users.some(item => item.hobbys && item.hobbys.first)); // true

answered May 10, 2019 at 9:12

Nikhil Aggarwal

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Comments

Kaushik · Accepted Answer · 2019-05-10 09:11:14Z

You can use "key" in obj also to check if a key is part if object.

const users = [{
  "type": "User",
  "name": "Sarah",
  "hobbys": {
    first: "something1",
    second: "something2"
  }
}];

const userWithFirstHobbyExists = users.some(({ hobbys }) => (
 typeof hobbys === 'object' && ('first' in hobbys )
));
console.log(userWithFirstHobbyExists);

Alternate and fast way to check is

    const users = [{
      "type": "User",
      "name": "Sarah",
      "hobbys": {
        first: "something1",
        second: "something2"
      }
    }];

    const userWithFirstHobbyExists = users.some(({ hobbys }) => (
     typeof hobbys === 'object' && hobbys['first'] !== undefined
    ));
    console.log(userWithFirstHobbyExists);

Manikandan Velayutham · Accepted Answer · 2019-05-10 09:20:02Z

0

const users = [{
  "type": "User",
  "name": "Sarah",
  "hobbys": {
    first: "somethig1",
    second: "something2"
  }
}];

const hobbyExists = users.some(({ hobbys }) => (typeof hobbys === 'object' && hobbys['first']));
console.log(hobbyExists);

answered May 10, 2019 at 9:20

Manikandan Velayutham

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Comments

Badri Chorapalli · Accepted Answer · 2019-05-10 09:35:35Z

0

function will return true if it has value else false

let jData = {
    "users": [{
        "type": "User",
        "name": "Sarah",
        "hobbys": {
            "first": "something1",
            "second": "something2"
        }
    }]
};

function hasValue(data, obj, key) {
    return data.some(item => item[obj] && item[obj][key]);
}
console.log(hasValue(jData.users, 'hobbys', 'second')) //true
console.log(hasValue(jData.users, 'hobbys', 'first')) // true
console.log(hasValue(jData.users, 'test', 'first'))  //false

answered May 10, 2019 at 9:35

Badri Chorapalli

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