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How to find if two arrays contain any common item in Javascript?
• Last Updated : 20 May, 2019

Given two arrays containing array elements and the task is to check if two arrays contain any common elements then it returns True otherwise return False.

Examples:

```Input: array1 = ['a', 'b', 'c', 'd', 'e']
array2 = ['f', 'g', 'c']
Output: true

Input: array1 = ['x', 'y', 'w', 'z']
array2 = ['m', 'n', 'k']
Output: false
```

There are many methods to solve this problem in JavaScript some of them are discussed below.

Method 1: Brute Force approach

• Compare each and every item from the first array to each and every item of second array.
• Loop through array1 and iterate it from beginning to the end.
• Loop through array2 and iterate it from beginning to the end.
• Compare each and every item from array1 to array2 and if it finds any common item then return true otherwise return false.

Example:

 `                    `

Output:

`false`

Time Complexity: O(M * N)

Method 2:

• Create an empty object and loop through first array.
• Check if the elements from the first array exist in the object or not. If it doesn’t exist then assign properties === elements in the array.
• Loop through second array and check if elements in the second array exists on created object.
• If element exist then return true else return false.

Example:

 `                    `

Output:

`false`

Time Complexity: O(M + N)

Method 3:

• Use the inbuilt ES6 function some() to iterate through each and every element of first array and to test the array.
• Use the inbuilt function includes() with second array to check if element exist in the first array or not.
• If element exist then return true else return false
 `                    `

Output:

`true` My Personal Notes arrow_drop_up