There are two different things that we can do with it: Using it as a matcher against DateTime objects and obtaining the next or previous DateTime to a given one according to the parsed expression.

There are also many flavours of DateTime representations in either the JVM or in JS land. cron4s supports a few out of the box and it also makes it easy to add your own types. Every single supported library out of box, or adapted to work with cron4s will support the same operations with the same semantics.

cron4s uses implicit classes to enrich the base expression types with the methods that operate on specific DateTime representations. There are specific packages containing the enrichments for each supported DateTime type, so be sure that you have always the correct imports for your DateTime library in your sources.

Now let’s take a look at what are the main operations:

• Matching Date & Time
• Forwards & Backwards In Time