30-seconds-of-code/snippets/filterNonUnique.md

title, tags

title	tags
filterNonUnique	array,beginner

Filters out the non-unique values in an array.

• Use Array.prototype.filter() for an array containing only the unique values.

const filterNonUnique = arr => arr.filter(i => arr.indexOf(i) === arr.lastIndexOf(i));

filterNonUnique([1, 2, 2, 3, 4, 4, 5]); // [1, 3, 5]