Data that updates the interface.
WHAT REACTIVE STATE IS
Values tracked by the framework, updating the interface when changed.
WHAT THE TWO PRIMITIVES ARE
One wrapping a single value One making an object reactive
WHAT TO BE CAREFUL WITH
Accessing the wrapped value, which requires a property in code but not in templates Losing reactivity by destructuring a reactive object
WHY THAT SECOND POINT
Extracted values are plain copies, disconnected from the source.
WHAT TO DO ABOUT IT
Use the provided helper preserving the connection.
WHAT COMPUTED VALUES ARE
Values derived from state, recalculated only when their dependencies change.
WHAT TO USE THEM FOR
Anything derived.
WHY
It prevents storing derived values in state, where they diverge.
WHAT WATCHERS ARE FOR
Reacting to a change with a side effect.
WHAT THEY ARE NOT FOR
Computing derived values.
WHAT TO PREFER
Computed values, wherever the result is simply derived.
WHAT TO KEEP MINIMAL
State, as in any framework.
