How to check if an object exists in JSON?

Question

JavaScript

[
  {
    id: '34bfd2234234177b17854d52'
    name: 'Miki',
    lastname: 'Adams',
    profession: 'Designer',
    email: '[email protected]',
    online: true,
    admin: false,
    createdAt: Wed Jan 21 2015 19:24:56 GMT+0300 (MSK),
    updatedAt: Thu Jan 22 2015 17:22:47 GMT+0300 (MSK),
    avatar: '',
  },
  {
    id: '54bfd2d81b9b177b17854d52'
    name: 'Artur',
    lastname: 'Altman',
    profession: 'Designer',
    email: '[email protected]',
    online: true,
    admin: false,
    createdAt: Wed Jan 21 2015 19:24:56 GMT+0300 (MSK),
    updatedAt: Thu Jan 22 2015 17:22:47 GMT+0300 (MSK),
    avatar: '',
  },
]

How to check if the following object is present in such an array?

[
  {
    id: '54bfd2d81b9b177b17854d52'
    name: 'Artur',
    lastname: 'Altman',
    profession: 'Designer',
    email: '[email protected]',
    online: true,
    admin: false,
    createdAt: Wed Jan 21 2015 19:24:56 GMT+0300 (MSK),
    updatedAt: Thu Jan 22 2015 17:22:47 GMT+0300 (MSK),
    avatar: '',
  }
]

Answer 1

The necessary information can be found here:
https://developer.mozilla.org/ru/docs/Web/JavaScri...
PS: There is a search by ID in the examples. =)

Answer 2

The same id is used for two objects - is this generally legal?)
On the topic: you must have some kind of criterion (a group of criteria) that allows you to uniquely distinguish one object from another (by its fields) - and usually this is just id.
parse json into an array, go around the resulting array, check for compliance with these unique criteria - it matches, which means this is the object.

Answer 3

var objects = [
    {
        "id": "34bfd2234234177b17854d52",
        "name": "Miki",
        "lastname": "Adams",
        "profession": "Designer",
        "email": "[email protected]",
        "online": true,
        "admin": false,
        "createdAt": "Wed Jan 21 2015 19: 24: 56 GMT + 0300(MSK)",
        "updatedAt": "Thu Jan 22 2015 17: 22: 47 GMT + 0300(MSK)",
        "avatar": ""
    },
    {
        "id": "54bfd2d81b9b177b17854d52",
        "name": "Artur",
        "lastname": "Altman",
        "profession": "Designer",
        "email": "[email protected]",
        "online": true,
        "admin": false,
        "createdAt": "Wed Jan 21 2015 19: 24: 56 GMT + 0300(MSK)",
        "updatedAt": "Thu Jan 22 2015 17: 22: 47 GMT + 0300(MSK)",
        "avatar": ""
    }
];

Array.prototype.containsObjectWithId = function(id){
    return !!this.filter(function(el){
        return el.hasOwnProperty('id') && el.id == id
    }).length;
}

console.log(objects.containsObjectWithId('54bfd2d81b9b177b17854d52')) // true
console.log(objects.containsObjectWithId('ok, this id do not exist')) // false

jsfiddle.net/r1duq6cy

Answer 4

collection.indexOf(object) !== -1

// upd

for (var i = 0, ii = collection.length; i < ii; ++i) {
  if (collection[i].id === object.id) {
    // your object
  }
}