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Remove duplicates from an array in JavaScript

Given an array containing items (numbers and strings), remove all the duplicates.

  • Set() – creating a set with an array automatically removes the duplicates
  • array.filter() – filter out already existing values
// Remove duplicates from an array

const array = [1, 1, 2, 3, 4, "a", "a", "b"];

// Set automatically removes duplicates
const setArray = [...new Set(array)];
console.log("setArray", setArray);
// "setArray" [1,2,3,4,"a","b"]

// Filters and keeps only the first occuring value
const filteredArray = array.filter(
  (item, index) => array.indexOf(item) === index
);
console.log("filteredArray", filteredArray);
// "filteredArray" [1,2,3,4,"a","b"]Code language: JavaScript (javascript)
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