Merge Two Arrays and Remove Duplicate

 JavaScript Program to Merge Two Arrays and Remove Duplicate Items

In this example, you will learn to write a JavaScript program that will merge two arrays and remove duplicate items from an array.

To understand this example, you should have the knowledge of the following JavaScript programming topics:

JavaScript Array concat()

JavaScript Set and WeakSet

JavaScript Spread Operator

Example 1: Using concat() and for Loop

In the above program, the two array elements are merged together and the duplicate elements are removed.

Here,

The two arrays are merged using the concat() method.

The for...of loop is used to loop through all the elements of arr.

The indexOf() method returns -1 if the element is not in the array.

Hence, during each iteration, if the element equals -1, the element is added to the uniqueArr array using the push() method.

Example 2: Using Spread Syntax and Set

In the above program, two arrays are merged together and Set is used to remove duplicate items from an array.

The Set is a collection of unique values.

Here,

Two array elements are merged together using the spread syntax ...

The array is converted to Set and all the duplicate elements are automatically removed.

The spread syntax ... is then used to include all the elements of the set back to an array.