Momentjs is easy to use, support various functions to operation of Date. It is defined object type and use like new Date(). For your convenience, it support unordered function parameter although it was deprecated now. momentjs was made to handle Date/Time and the set of these concept. For this reason, It can be a OOP library.
One of the biggest difference is that date-fns is immutable but momentjs is mutable. date-fns return new Date instance from function which was run. But momentjs change its own state.
Chart.js is has 8 different types of data display, each of which animated and customizable. Chart.js allows you to create simple HTML5 charts using the tag, with great rendering performance on all modern browsers. Definitely one of the most useful and elegant libraries in the list.