Remove duplicate values from JS array

Removing duplicate values from a JavaScript array is a common task, and thankfully, JavaScript offers several easy ways to handle it. Whether you're cleaning up user input, processing data, or just organizing a list, here's how you can do it effectively.

 Method 1: Using a Set (ES6)

The simplest and most popular way:

const numbers = [1, 2, 2, 3, 4, 4, 5];

const uniqueNumbers = [...new Set(numbers)];

console.log(uniqueNumbers); // [1, 2, 3, 4, 5]

• Set automatically removes duplicates.
  
• The spread operator (...) converts the Set back to an array.
  

 Method 2: Using filter() and indexOf()

This is another common method that works in all browsers:

const numbers = [1, 2, 2, 3, 4, 4, 5];

const uniqueNumbers = numbers.filter((value, index, self) => self.indexOf(value) === index);

console.log(uniqueNumbers); // [1, 2, 3, 4, 5]

It keeps only the first occurrence of each value.

 Method 3: For Complex Objects (using reduce() or custom logic)

For arrays of objects, you’ll need more advanced logic, like comparing specific keys.

 Quick Tips:

• Use Set for quick and clean results with primitive values.
  
• Use filter() if you want more control or need older browser support.
  
• For large datasets, performance may vary—test your method when needed.
  

Removing duplicates keeps your data clean and efficient. With these simple tools, JavaScript makes it a breeze!