BloomContext<T> class

Token representing an ambient context value of type T.

Context allows passing data down through a subtree without manually threading properties through every intermediate component ("prop drilling"). A context is created via createContext, injected into a subtree via provide, and consumed inside descendant components via useContext.

Zone-Based Propagation and Limitations

Context values are propagated through Dart Zone values captured during synchronous tree mounting and SSR rendering.

Important Gotcha: When a reactive boundary (such as Live or Show) rebuilds in response to a signal update, its builder callback executes in the Zone captured when that reactive effect was originally mounted. If an ancestor provider dynamically changes the value it supplies, descendant reactive rebuilds will continue to read the value from their initial mount zone unless the provider itself triggers a rebuild of the entire subtree. For dynamic state that changes over time, use Signal<T> instead of relying on mutable context.

final themeContext = createContext('light');

BloomNode themedCard() {
  final theme = useContext(themeContext);
  return Div(
    className: 'card card-$theme',
    text: 'Current theme: $theme',
  );
}

BloomNode app() => themeContext.provide(
  'dark',
  Div(
    children: [
      themedCard(),
    ],
  ),
);

Constructors

BloomContext(T defaultValue)

Creates a new ambient BloomContext token with the specified defaultValue.

Properties

defaultValue → T

The fallback value returned by useContext when no matching provider exists in the ancestor hierarchy.

final

hashCode → int

The hash code for this object.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

zoneKey → Object

The unique key used to look up and store this context's value within the ambient Zone.

final

Methods

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

provide(T value, BloomNode child) → BloomNode

Provides value to all children in the child subtree.

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited