If you had a list of chores, you might separate them with commas:

dishes, vacuum, tidy

A trailing comma is simply a comma that comes after the last item in our list. It’s not required, but in some instances in JS we’re allowed to put it there:

dishes, vacuum, tidy,

There are a number of reasons why you may want to include a trailing comma. Think about a scenario where you have to programmatically add elements to an array:

• Without trailing commas, most values can be added to the array as value + ',' however you then need to add in special logic to ensure that last item added to the array doesn’t include a comma after it.