You Can Filter Like That?

One of the joys of programming is stumbling across novel ways to solve common problems.

For example, take the totally banal task of filtering falsy values from an array.

I typically perform this task in one of two ways.

Either, passing a function to JavaScript’s Array.prototype.filter that simply returns each value in the array and relies on truthiness for filtering:

const array = [1, 2, undefined, 4]
const filteredArray = array.filter(value => value)

Or, leveraging a utility like LoDash’s compact:

const array = [1, 2, undefined, 4]
const filteredArray = _.compact(array)

While both approaches solve the problem, both feel inelegant. In the first example I dislike the redundancy of (value => value). In the second, I feel guilty reaching for a utility when JavaScript provides native array filtering.

This week, I came across a third approach I find much more appealing:

const array = [1, 2, undefined, 4]
const filteredArray = array.filter(Boolean)

Native and not redundant!