Remove Duplicates from an Array

Published on

NaN

Initial array:

const numbers = [1, 1, 1, 3, 3, 2, 2, 5, 6, 7, 7];

Using a Set

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

Array.prototype.reduce

const uniqueNumbers = numbers.reduce((previousValue, currentValue) => {
  return previousValue.includes(currentValue) ? previousValue : [...previousValue, currentValue];
}, []);

If you are not familiar with reduce, use this documentation.

Array.prototype.filter

const uniqueNumbers = numbers.filter((element, index) => {
  return numbers.indexOf(element) === index;
});