Determine if an object is present in a JavaScript array

This post will discuss how to determine whether an object is present in a JavaScript array.

JavaScript native methods indexOf() and includes() compare by using the strict equality operator (===). This won’t work for object comparison, as shown below:

var key1 = { name : 'Joey' };

var key2 = { name : 'Joey' };

console.log(key1 === key2); // false

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This post provides an overview of some of the available alternatives to accomplish this.

1. Using `_.some()` method

If you’re already using the Lodash library, consider using the _.some method. It returns true if a JavaScript array contains an object.

var _ = require('lodash');

var obj = [{ one : 1 }, { two : 2}, { three : 3 }];

var key = { two : 2};

console.log(_.some(obj, key));

Output: true

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Alternatively, you can use the _.some method of the Underscore library.

var _ = require('underscore');

var obj = [{ one : 1 }, { two : 2}, { three : 3 }];

var key = { two : 2};

console.log(_.some(obj, key));

Output: true

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2. Using `JSON.stringify()` function

Here, the idea is to convert the given object into a string using the JSON.stringify() method. Then we compare the string representation of the object against each entry in the array using the strict equality operator (===). This can be done using any of the methods discussed here.

var obj = [{ one : 1 }, { two : 2}, { three : 3 }];

var key = { two : 2};

var str = JSON.stringify(key);

var isPresent = obj.some(item => JSON.stringify(item) === str);

console.log(isPresent);

Output: true

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That’s all about checking if an object is present in a JavaScript array.

Determine if an object is present in a JavaScript array

1. Using _.some() method

2. Using JSON.stringify() function

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1. Using `_.some()` method

2. Using `JSON.stringify()` function