${carat} is not working; at least on FireFox; Try: md `To confirm that our data is sorted, you could inspect it above using the ►, or we could display the sorted data in a chart:`

Thanks! ▸

Typo: progrms --> programs

It might be worth briefly discussing how date objects in JavaScript are assumed to be UTC (GMT) when creating them as this is something that can trip you up (it still trips me up!) Formatting a date will typically give you its value in local time, but when parsing and formatting it's good to be cautious of time zones and how JS treats dates as UTC. There's also the `Date.prototype.toLocaleString()` method that's built in which can be helpful for formatting dates without a library. It could be worth noting how to convert between date objects and timestamps, and how the latter are useful for comparing dates in JS.

Ah, good point! Will see if I can work this in!

Since you are using lodash, you can use lodash for these too, which for basic needs are more easy to use than the reduce approach: _.sumBy(data, "HousingUnitsAdded"). I also often use _.countBy.

It looks like this line must be changed to parser = d3.timeParse("%x %X") due to the data changing. Someone please let me know if you are seeing something different.