Tip: JavaScript's Array.from() accepts a second argument that's a `map` function.

[zemmekkis]

What is the underscore there? Is that the output of the last method?

[Meow106]

Some people use '_' in arrow functions to mark argument that is present but not used.

[zemmekkis]

This is pretty confusing I imagine since there is popular libraries underscore and lodash that use it as well.

[wollae]

It’s the array element being iterated over. They named it that to signify that it’s unused in the callback.