Hmr class

Child-side runtime API. Lets the supervised application react to reload lifecycle events the hmr supervisor emits.

Usage from your bin/main.dart:

import 'package:hmr/runtime.dart';

void main() {
  Hmr.instance.init();
  Hmr.instance.onReload((_) => print('reloaded'));
  Hmr.instance.onRestart((_) => print('restarted — re-initialising state'));
  runApp();
}

When not running under the supervisor (HMR_PARENT_PID unset), init is a no-op and registered handlers simply never fire. This means production builds need no conditional imports.

Constructors

Hmr.forTesting(): Fresh, isolated instance for unit tests. Bypasses the static singleton so each test starts with an empty handler list.
factory

Properties

hashCode → int: The hash code for this object.
no setterinherited
isActive → bool: True when the process was launched by the hmr supervisor (the supervisor sets HMR_PARENT_PID in the child's environment).
no setter
runtimeType → Type: A representation of the runtime type of the object.
no setterinherited

Methods

dispatch(RunnerEvent event) → void: Routes an event to every registered handler, isolating errors so a misbehaving hook can never crash the supervised app.
init() → void: Registers the ext.hmr.dispatch VM service extension so the parent can forward events. Safe to call multiple times. No-op when isActive is false, so production code can call it unconditionally.
noSuchMethod(Invocation invocation) → dynamic: Invoked when a nonexistent method or property is accessed.
inherited
on<E extends RunnerEvent>(void handler(E event)) → void: Registers a handler for events of type E. Subscribe to RunnerEvent to receive every event.
onFileCreated(void handler(FsCreated change)) → void
onFileDeleted(void handler(FsDeleted change)) → void
onFileModified(void handler(FsModified change)) → void
onFileMoved(void handler(FsMoved change)) → void
onReload(void handler(ReloadSucceeded event)) → void: Fires after every successful hot reload (state preserved).
onRestart(void handler(ReloadSucceeded event)) → void: Fires after every successful hot restart (state lost — main() re-runs). Use this to re-warm caches, re-open connections, etc.
toString() → String: A string representation of this object.
inherited

Operators

operator ==(Object other) → bool: The equality operator.
inherited

Static Properties

instance → Hmr: Process-wide instance. The child registers a single VM service extension — there is no useful reason to have multiple Hmrs in the same isolate.
final