30-seconds-of-code/snippets/unique-values-of-array.md

Unique values of array

Use reduce() to accumulate all unique values in an array. Check if each value has already been added, using indexOf() on the accumulator array.

var uniqueValues = arr =>
  arr.reduce( (acc, val) => {
    if(acc.indexOf(val) === -1)
      acc.push(val);
      return acc;
  }, []);