Classes encourage you to think about the world as a hierarchical collection of objects. Objects bundle behavior, data, and state together in a way that draws boundaries between instances of things, like chess pieces on a board.

Functions encourage you to think about the world as a series of data transformations. Functions take data as input and return a transformed output. For example, a function might take the entire state of a chess board and a move as inputs, and return the new state of the board as output.

Classes or Functions?

If you’re unsure, default to functions. Reach for classes when you need something long-lived and stateful that would be easier to model if you could share behavior and data structure via inheritance. This is often the case for:

• Video games
• Simulations
• GUIs

References

• boot.dev