Discuss: Add underscore as dev dependency

[dsingleton]

We're mostly writing ES6, but there are still some things which are clunky/verbose, like flattening an array and other functional behaviours.

Theres have been a few times where i've wanted to add underscore as a dependency, but i'm wary of node dependency soup. That said, underscore is pretty mature.

Creating an issue as a reminder for the new year, but any objections to adding it to the project?

[robinwhittleton]

I’m pro in terms of adding in extra functionality that is lacking in the standard lib, but I’d want to make sure that we’re using standard lib options over underscore where possible, especially as we’re stipulating modern Node.