trigger<T> function

T trigger<T>(T fn())

Runs fn while collecting the nodes it reads, then propagates those nodes.

This is useful for in-place mutations that keep object identity the same. Reads inside fn decide which dependencies should notify subscribers after the callback finishes.

Implementation

@pragma("vm:prefer-inline")
@pragma("wasm:prefer-inline")
@pragma("dart2js:prefer-inline")
T trigger<T>(T Function() fn) {
  final sub = EffectNode(() {}, detach: true);
  final prevSub = setActiveSub(sub);

  try {
    return fn();
  } finally {
    activeSub = prevSub;
    sub.flags = ReactiveFlags.none;
    var link = sub.deps;
    while (link != null) {
      final dep = link.dep;
      link = unlink(link, sub);
      final subs = dep.subs;
      if (subs != null) {
        propagate(subs, runDepth > 0);
        shallowPropagate(subs);
      }
    }
    if (batchDepth == 0) {
      flushEffects();
    }
  }
}