Posted by Arjun on Saturday 18th August 2018

How to Remove Duplicates from JavaScript Array

How to

You can use the JavaScript built in object Set to keep unique values of any type. You can make use of Set to remove duplicate entries from a JavaScript array. Here is how the code looks

let technologies = ['JS','PHP','Ruby','Node','Python','PHP','JS']
technologies = [...new Set(technologies)]
console.log(technologies)

Set will only include distinct elements from that array, aka no duplicate. however, the Set doesn't remove duplicates from the array of objects. In this case, we can use ES6 filter and map functions to remove duplicates.

let technologies = [{'technology': 'PHP'},{'technology':'Node'},{'technology':'PHP'}]
technologies = technologies.filter((obj, index) => { 
  return technologies.map(obj => obj['technology']).indexOf(obj['technology']) === index;   
});

console.log(technologies)