Is there a function which returns true or false when searching for an object in an array of objects?

Question

I'm looking for a good way to check if an object exist in an array of objects. The intended result is true when all keys/values are present in the same object in that array.

The answers I found by browsing stackoverflow like Find object by id in an array of JavaScript objects which is using jQuery.grep or Find a value in an array of objects in Javascript return the found object. What I'm looking for is a boolean result (not the found object).

I know that I can loop for all array elements and then compare each value....etc

But what I mean is if there is a way to use JS methods like this:

var listOfObjecs = [
 {id: 1, name: "Name 1", score: 11},
 {id: 2, name: "Name 2", score: 22},
 {id: 3, name: "Name 3", score: 33},
 {id: 4, name: "Name 4", score: 44},
 {id: 5, name: "Name 5", score: 55},
];

var isObjectExist = function(search){
  return listOfObjecs.filter(function(obj){
     if(obj.id===search.id && obj.name===search.name && obj.score===search.score){
          return true;
     }
     return false;
  });
}

console.log( isObjectExist({id: 3, name: "Name 3", score: 33}) );
//outputs the found object [{id: 3, name: "Name 3", score: 33}]

console.log( isObjectExist({id: 9, name: "Name 3", score: 33}) );
//outputs an empty object []

This is because:

The filter() method creates a new array with all elements that pass the test implemented by the provided function.

If there is no native JavaScript method (returning true or false) how can update the isObjectExist() function to return true or false?

[`Array.prototype.some()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/some) — Pointy, Jan 30 '17 at 19:28
What about `!!arr.find(function(){...});` See [`Array.find()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/find) — zero298, Jan 30 '17 at 19:29
@zero298 The find() method returns a value of the first element in the array that satisfies the provided testing function. Otherwise undefined is returned. So **no boolean result**. — Ala Eddine JEBALI, Jan 30 '17 at 19:30
Possible duplicate of [How do I check if an array includes an object in JavaScript?](http://stackoverflow.com/questions/237104/how-do-i-check-if-an-array-includes-an-object-in-javascript) — Heretic Monkey, Jan 30 '17 at 19:31
That's why you add `!!` to the return. This casts truthy (an object) to `true` and falsy (undefined) to `false`. — zero298, Jan 30 '17 at 19:31
@zero298 wrong function for the job, will fail if the entity being sought has a falsey value. — Alnitak, Jan 30 '17 at 19:33
I recommend reading through the documentation for arrays to see all the functions, because there really aren't that many, and it will save you lots of time in the future. — 4castle, Jan 30 '17 at 19:44

score 104 · Accepted Answer · edited Jan 30 '17 at 19:45

104

The Array.prototype.some method:

The some() method checks if any of the elements in an array pass a test (provided as a function). The some() method executes the function once for each element present in the array: If it finds an array element where the function returns a true value, some() returns true (and does not check the remaining values)

edited Jan 30 '17 at 19:45

Alnitak

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answered Jan 30 '17 at 19:29

Matt Spinks

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aarkerio · Answer 2 · 2021-08-14T02:22:59.090

8

This works for me:

const findInArray = (myArray, item) => {
 !!myArray.find((el) => el == item)
};

Update, even easier:

 ['cat', 'dog', 'bat'].includes('dog');

edited Aug 14 '21 at 02:22

answered Sep 01 '20 at 20:14

aarkerio

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score 7 · Answer 3 · answered Feb 19 '19 at 16:12

I'm sharing an example based on comments above, it may help others:

  const listOfObjecs = [
    { id: 1, name: "Name 1", score: 11 },
    { id: 3, name: "Name 3", score: 33 },
    { id: 2, name: "Name 2", score: 22 },
    { id: 3, name: "Name 3", score: 33 },
    { id: 4, name: "Name 4", score: 44 },
    { id: 5, name: "Name 5", score: 55 },
    { id: 3, name: "Name 3", score: 33 },
  ];
  const search1 = { id: 3, name: "Name 3", score: 33 };
  const search2 = { id: 9, name: "Name 3", score: 33 };

  // Using Array.prototype.some()
  const resSomeSearch1 = listOfObjecs.some(item => JSON.stringify(item) === JSON.stringify(search1));
  console.log(`resSome(search1): ${resSomeSearch1}`); // outputs: true
  const resSomeSearch2 = listOfObjecs.some(item => JSON.stringify(item) === JSON.stringify(search2));
  console.log(`resSome(search2): ${resSomeSearch2}`); // outputs: false

  // Using Array.prototype.filter()
  const resFilterSearch1 = !!listOfObjecs.filter(item => JSON.stringify(item) === JSON.stringify(search1)).length;
  console.log(`resFilter(search1): ${resFilterSearch1}`); // outputs: true
  const resFilterSearch2 = !!listOfObjecs.filter(item => JSON.stringify(item) === JSON.stringify(search2)).length;
  console.log(`resFilter(search2): ${resFilterSearch2}`); // outputs: false

  // Using Array.prototype.find()
  const resFindSearch1 = !!listOfObjecs.find(item => JSON.stringify(item) === JSON.stringify(search1));
  console.log(`resFind(search1): ${resFindSearch1}`); // outputs: true
  const resFindSearch2 = !!listOfObjecs.find(item => JSON.stringify(item) === JSON.stringify(search2));
  console.log(`resFind(search2): ${resFindSearch2}`); // outputs: false

score 3 · Answer 4 · answered Apr 18 '20 at 16:33

The find() method returns a value of the first element in the array that satisfies the provided testing function. Otherwise undefined is returned. So no boolean result.

@AlaDejbali's comment on his post.

Let's take this array :

var arr = [{
        name: "Ala",
        age: 20,
    },
    {
        name: "Jhon",
        age: 22,
    },
    {
        name: "Melissa",
        age: 12,
    },
];

Of course, find() returns the whole object inside your array but that depends on your implemented function inside find for example :

function findObject(arr, value) {
    if (Array.isArray(arr)) {
        return arr.find((value) => {
            return value.age === 20;
        });
    }
}

When we call this function like this :

console.log(findObject(arr, 20));

The resul will be :

{name: "Ala", age: 20}

And as far as we know undefined is not an object so we can test the returned result :

function findObject(arr, value) {
    const element = arr.find((value) => {
        return value.age === 20;
    });
    return typeof element === "object" ? true : false;
}

Or in other way :

function findObject(arr, value) {
        const element = arr.find((value) => {
            return value.age === 20;
        });
        return typeof element === "undefined" ? false : true;
    }

score 0 · Answer 5 · answered Apr 27 '20 at 18:16

return boolean value if an object exists in array of objects.

var listOfObjecs = [
  { id: 1, name: "Name 1", score: 11 },
  { id: 2, name: "Name 2", score: 22 },
  { id: 3, name: "Name 3", score: 33 },
  { id: 4, name: "Name 4", score: 44 },
  { id: 5, name: "Name 5", score: 55 },
];

var object = { id: 3, name: "Name 3", score: 33 };
var booleanValue = listOfObjecs.filter((item) => 
                   item.id === object.id && 
                   item.name === object.name && 
                   item.score === object.score).length > 0
console.log({booleanValue})

if is not found it will return: Cannot read property 'length' of undefined — utiq, Jul 07 '22 at 00:40

score 0 · Answer 6 · answered Nov 01 '22 at 11:15

0

This is a snippet that complements the answer provided by @MattSpinks

A basic example using the some() JS method

const ids = [1,2,3,4,5]

console.log(
  ids.some(id => id == 1) // true
)

console.log(
  ids.some(id => id == 0) // false
)

answered Nov 01 '22 at 11:15

Gass

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Is there a function which returns true or false when searching for an object in an array of objects?

6 Answers6