How to find a value in an array of objects in JavaScript?

Question

I have an array of objects:

Object = {
   1 : { name : bob , dinner : pizza },
   2 : { name : john , dinner : sushi },
   3 : { name : larry, dinner : hummus }
}

I want to be able to search the object/array for where the key is "dinner", and see if it matches "sushi".

I know jQuery has $.inArray, but it doesn't seem to work on arrays of objects. Or maybe I'm wrong. indexOf also seems to only work on one array level.

Is there no function or existing code for this?

Answer 1

If you have an array such as

var people = [
  { "name": "bob", "dinner": "pizza" },
  { "name": "john", "dinner": "sushi" },
  { "name": "larry", "dinner": "hummus" }
];

You can use the filter method of an Array object:

people.filter(function (person) { return person.dinner == "sushi" });
  // => [{ "name": "john", "dinner": "sushi" }]

In newer JavaScript implementations you can use a function expression:

people.filter(p => p.dinner == "sushi")
  // => [{ "name": "john", "dinner": "sushi" }]

---

You can search for people who have "dinner": "sushi" using a map

people.map(function (person) {
  if (person.dinner == "sushi") {
    return person
  } else {
    return null
  }
}); // => [null, { "name": "john", "dinner": "sushi" }, null]

or a reduce

people.reduce(function (sushiPeople, person) {
  if (person.dinner == "sushi") {
    return sushiPeople.concat(person);
  } else {
    return sushiPeople
  }
}, []); // => [{ "name": "john", "dinner": "sushi" }]

I'm sure you are able to generalize this to arbitrary keys and values!

Answer 2

jQuery has a built-in method jQuery.grep that works similarly to the ES5 filter function from @adamse's Answer and should work fine on older browsers.

Using adamse's example:

var peoples = [
  { "name": "bob", "dinner": "pizza" },
  { "name": "john", "dinner": "sushi" },
  { "name": "larry", "dinner": "hummus" }
];

you can do the following

jQuery.grep(peoples, function (person) { return person.dinner == "sushi" });
  // => [{ "name": "john", "dinner": "sushi" }]

Answer 3

If you're going to be doing this search frequently, consider changing the format of your object so dinner actually is a key. This is kind of like assigning a primary clustered key in a database table. So, for example:

Obj = { 'pizza' : { 'name' : 'bob' }, 'sushi' : { 'name' : 'john' } }

You can now easily access it like this: Object['sushi']['name']

Or if the object really is this simple (just 'name' in the object), you could just change it to:

Obj = { 'pizza' : 'bob', 'sushi' : 'john' }

And then access it like: Object['sushi'].

It's obviously not always possible or to your advantage to restructure your data object like this, but the point is, sometimes the best answer is to consider whether your data object is structured the best way. Creating a key like this can be faster and create cleaner code.

Answer 4

var getKeyByDinner = function(obj, dinner) {
    var returnKey = -1;

    $.each(obj, function(key, info) {
        if (info.dinner == dinner) {
           returnKey = key;
           return false; 
        };   
    });

    return returnKey;       

}

jsFiddle.

So long as -1 isn't ever a valid key.

Answer 5

You can find the object in array with Alasql library:

var data = [ { name : "bob" , dinner : "pizza" }, { name : "john" , dinner : "sushi" },
     { name : "larry", dinner : "hummus" } ];

var res = alasql('SELECT * FROM ? WHERE dinner="sushi"',[data]);

Try this example in jsFiddle.

Answer 6

You can use a simple for in loop:

for (prop in Obj){
    if (Obj[prop]['dinner'] === 'sushi'){

        // Do stuff with found object. E.g. put it into an array:
        arrFoo.push(Obj[prop]);
    }
}

The following fiddle example puts all objects that contain dinner:sushi into an array:

https://jsfiddle.net/3asvkLn6/1/

Answer 7

There's already a lot of good answers here so why not one more, use a library like lodash or underscore :)

obj = {
   1 : { name : 'bob' , dinner : 'pizza' },
   2 : { name : 'john' , dinner : 'sushi' },
   3 : { name : 'larry', dinner : 'hummus' }
}

_.where(obj, {dinner: 'pizza'})
>> [{"name":"bob","dinner":"pizza"}]

Answer 8

I had to search a nested sitemap structure for the first leaf item that machtes a given path. I came up with the following code just using .map() .filter() and .reduce. Returns the last item found that matches the path /c.

var sitemap = {
  nodes: [
    {
      items: [{ path: "/a" }, { path: "/b" }]
    },
    {
      items: [{ path: "/c" }, { path: "/d" }]
    },
    {
      items: [{ path: "/c" }, { path: "/d" }]
    }
  ]
};

const item = sitemap.nodes
  .map(n => n.items.filter(i => i.path === "/c"))
  .reduce((last, now) => last.concat(now))
  .reduce((last, now) => now);

Answer 9

We use object-scan for most of our data processing. It's conceptually very simple, but allows for a lot of cool stuff. Here is how you would solve your question

// const objectScan = require('object-scan');

const findDinner = (dinner, data) => objectScan(['*'], {
  abort: true,
  rtn: 'value',
  filterFn: ({ value }) => value.dinner === dinner
})(data);

const data = { 1: { name: 'bob', dinner: 'pizza' }, 2: { name: 'john', dinner: 'sushi' }, 3: { name: 'larry', dinner: 'hummus' } };

console.log(findDinner('sushi', data));
// => { name: 'john', dinner: 'sushi' }

.as-console-wrapper {max-height: 100% !important; top: 0}

<script src="https://bundle.run/object-scan@13.8.0"></script>

Disclaimer: I'm the author of object-scan

Answer 10

If You want to find a specific object via search function just try something like this:

    function findArray(value){

        let countLayer = dataLayer.length;
        for(var x = 0 ; x < countLayer ; x++){

            if(dataLayer[x].user){
                let newArr = dataLayer[x].user;
                let data = newArr[value];
                return data;
            }

        }

        return null;

    }

    findArray("id");

This is an example object:

layerObj = {
    0: { gtm.start :1232542, event: "gtm.js"},
    1: { event: "gtm.dom", gtm.uniqueEventId: 52},
    2: { visitor id: "abcdef2345"},
    3: { user: { id: "29857239", verified: "Null", user_profile: "Personal", billing_subscription: "True", partners_user: "adobe"}
}

Code will iterate and find the "user" array and will search for the object You seek inside.

My problem was when the array index changed every window refresh and it was either in 3rd or second array, but it does not matter.

Worked like a charm for Me!

In Your example it is a bit shorter:

function findArray(value){

    let countLayer = Object.length;
    for(var x = 0 ; x < countLayer ; x++){

        if(Object[x].dinner === value){
            return Object[x];
        }

    }

    return null;

}

findArray('sushi');