docs: document when and asyncWhen options #249

docs/docs/api/reaction.mdx

@@ -98,13 +98,19 @@ dispose();
 
 ## when
 
-#### `ReactionDisposer when(bool Function(Reaction) predicate, void Function() effect)`
+#### `ReactionDisposer when(bool Function(Reaction) predicate, void Function() effect, {String? name, ReactiveContext? context, int? timeout, void Function(Object, Reaction)? onError})`
 
 Monitors the observables used inside `predicate()` and runs the `effect()`
 _when_ it returns `true`. After the `effect()` is run, `when` automatically
 disposes itself. So you can think of _when_ as a _one-time_ `reaction`. You can
 also dispose `when()` pre-maturely.
 
+**Optional parameters:**
+- **`name`**: Debug name for this reaction
+- **`context`**: The `ReactiveContext` to use. By default the `mainContext` is used.
+- **`timeout`**: Number of milliseconds to wait for the predicate to become true. If the timeout elapses first, `when` disposes itself and throws a `MobXException`, unless `onError` is set.
+- **`onError`**: By default, any exception thrown inside a reaction will be logged but not further thrown. This option allows overriding that behavior.
+
 ```dart
 import 'package:mobx/mobx.dart';
 
@@ -121,12 +127,17 @@ greeting.value = 'Hello MobX'; // Causes a change, runs effect and disposes
 
 ## asyncWhen
 
-#### `Future<void> asyncWhen(bool Function(Reaction) predicate)`
+#### `Future<void> asyncWhen(bool Function(Reaction) predicate, {String? name, int? timeout, ReactiveContext? context})`
 
 Similar to `when` but returns a `Future`, which is fulfilled when the
 `predicate()` returns _true_. This is a convenient way of waiting for the
 `predicate()` to turn `true`.
 
+**Optional parameters:**
+- **`name`**: Debug name for this reaction
+- **`timeout`**: Number of milliseconds to wait for the predicate to become true. If the timeout elapses first, the returned `Future` completes with a `MobXException`.
+- **`context`**: The `ReactiveContext` to use. By default the `mainContext` is used.
+
 ```dart
 final completed = Observable(false);