Removing Duplicate From Arrays

To remove duplicates from an array in JavaScript, you can use various approaches. Here are a few common methods:

1. Using the Set data structure:
   The Set object in JavaScript allows you to store unique values. By converting the array into a Set and then back into an array, you can automatically remove duplicates.

   var array = [1, 2, 3, 4, 2, 1, 5, 3];
   var uniqueArray = Array.from(new Set(array));
   console.log(uniqueArray); // [1, 2, 3, 4, 5]

In this example, the array [1, 2, 3, 4, 2, 1, 5, 3] is converted to a Set using new Set(array). The Set automatically removes duplicates. Finally, Array.from() is used to convert the Set back into an array.

2. Using the filter() method:
   The filter() method can be used to create a new array that contains only the unique elements from the original array.

 var array = [1, 2, 3, 4, 2, 1, 5, 3];
 var uniqueArray = array.filter((value, index, self) => {
   return self.indexOf(value) === index;
 });
 console.log(uniqueArray); // [1, 2, 3, 4, 5]

In this example, the filter() method is applied to the array, and the callback function checks if the index of the current element (self.indexOf(value)) is equal to the current index. If they match, it means the element is the first occurrence in the array, and it is added to the new uniqueArray.

3. Using a temporary object or map:
   You can iterate over the array and store the unique elements in a temporary object or map. Then, extract the values to get an array without duplicates.

 var array = [1, 2, 3, 4, 2, 1, 5, 3];
 var uniqueArray = [];
 var tempObj = {};
 for (var i = 0; i < array.length; i++) {
   var element = array[i];
   if (!tempObj[element]) {
     uniqueArray.push(element);
     tempObj[element] = true;
   }
 }
 console.log(uniqueArray); // [1, 2, 3, 4, 5]

In this example, the tempObj object is used to keep track of unique elements encountered so far. If an element is not present in the tempObj, it is added to the uniqueArray and marked as true in the tempObj.

These are just a few examples of how you can remove duplicates from an array in JavaScript. Choose the method that best suits your needs and the specific requirements of your application.