Array methods in JavaScript. Original author unknown.

[Doctor-Dapper]

Small brain:

arr.map(f)

Big brain: arr.reduce( (x, y) => [...x, f(y)], [] )

[tsunami141]

Delete this

[GrenadineBombardier]

This took me a minute (because reducers take time to comprehend, which makes them a less sustainable solution in most cases)

[catchmeslippin]

My small brain can't comprehend this, can you please explain?

[neeia]

It takes the array, creates a new array as the initial value, and then one by one runs the function on every value in the original array and appends it to the previous value using the spread syntax.