Check if same object exists in an array - Javascript

Question

I have an array of objects as follows

[{name: "jack", age: 10}, {name: "john", age: 15}]

Consider that i have an object

{name: "jack", age: 10}

Now i need to check if this object exist in the array. If all the properties(name, age) of the object matches, then display an alert on the page.

How to accomplish this using pure javascript?

accomplish it by checking all the "primitive" properties match - Object.keys/Object.values or Object.entries can help — Jaromanda X, May 25 '18 at 06:58
possible duplicate of https://stackoverflow.com/questions/4587061/how-to-determine-if-object-is-in-array — DaCh, May 25 '18 at 07:00
Possible duplicate of [How to determine if object is in array](https://stackoverflow.com/questions/4587061/how-to-determine-if-object-is-in-array) — DaCh, May 25 '18 at 07:00

Nikhil Aggarwal · Accepted Answer · 2018-05-25T07:06:35.350

0

Use Array.some, Array.every and Object.entries

A match will be counted if

There are equal number of keys
There is a match for every key/value pair

var arr = [{name: "jack", age: 10}, {name: "john", age: 15}];

var input = {name: "jack", age: 10};

var result = arr.some((o) => Object.entries(input).every(([k,v]) => o[k] === v) && Object.keys(input).length === Object.keys(o).length);

console.log(result);

edited May 25 '18 at 07:06

answered May 25 '18 at 07:00

Nikhil Aggarwal

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@NinaScholz - Updated – Nikhil Aggarwal May 25 '18 at 07:04
nearly. you need a check for the key as well (`undefined` is a value or a state). – Nina Scholz May 25 '18 at 07:06
@NinaScholz - Need a check for the keys? Can you please explain? Not able to get your point – Nikhil Aggarwal May 25 '18 at 07:11
if `input` has `foo: undefined` and in array does no object has this key, the value is missing, because for not set properties, the value is `undefined`, which is in this case a state and in the given object for checking, it's a value. – Nina Scholz May 25 '18 at 07:16
@NinaScholz - Makes sense. However, I think the length check will negate this case. What do you think? – Nikhil Aggarwal May 25 '18 at 07:18
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/171747/discussion-between-nina-scholz-and-nikhil-aggarwal). – Nina Scholz May 25 '18 at 07:19

score 0 · Answer 2 · answered May 25 '18 at 07:04

Try this:

var data = [{name: "jack", age: 10}, {name: "john", age: 15}];
var input = {name: "jack", age: 10};
for(var i=0;i<data.length;i++)
{
    if(data[i].name==input.name && data[i].age == input.age)
    {
        alert('matched');
        break;
    }
}

wiesion · Answer 3 · 2018-05-25T07:15:55.060

0

This may be a bad performing method, but it would cover nested object cases with ease. Also this is only suited if ALL key/value pairs must match and that the key/value pairs were defined in the same order.

let c = [{name: "jack", age: 10}, {name: "john", age: 15}],
    s = {name: "jack", age: 10};

console.log(c.filter(e => JSON.stringify(s) === JSON.stringify(e)));

edited May 25 '18 at 07:15

answered May 25 '18 at 07:12

wiesion

2,349
12
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No. This will not work. If the order of keys are different it will fail. – Nikhil Aggarwal May 25 '18 at 07:12
Yes, only if the objects were declared the same way with the same key order, will add to response. – wiesion May 25 '18 at 07:15

score 0 · Answer 4 · answered May 25 '18 at 07:23

You can try this if you don't want to check for index of object inside array object

var obj = [{name: "jack", age: 10}, {name: "john", age: 15}];

var checkObj = {name: "john", age: 15};

if(JSON.stringify(obj).indexOf(JSON.stringify(checkObj)) >= 0){
  console.log("Object Available");
}else{
  console.log("Object Not Available");
}

Check if same object exists in an array - Javascript

4 Answers4