Remove Duplicates

removeDuplicates.js

function removeDuplicates(arr) {
  return arr.filter((el, idx) => arr.indexOf(el) === idx)
}

function removeDuplicates(numbers) {
    return numbers.reduce((accumulator, currentValue) => {
        if(accumulator.indexOf(currentValue) === -1) {
            accumulator.push(currentValue)
        }

        return accumulator

    }, []);
}


function allUnique(numbers) {
    return numbers.reduce((accumulator, currentValue, index) => {
        if (numbers.indexOf(currentValue) !== index) return false

        return accumulator
    }, true);
}