Persistent Changes

Immutable data cannot change. The state of your applications must change, however, otherwise they would be completely static. To cope with changing the application state, Immutable.js collections use persistent changes. A persistent change involves first copying the target collection and then making the change in the copy.

The focus of this chapter is on some of the collection methods that implement persistent changes. You'll learn about the following:

• Adding values to collections
• Setting and updating collection values
• Removing values from collections
• Emptying collections
• Tracking the change history of collections