Class Watcher

Watcher for tracking changes to observable properties

Automatically tracks @observable and @computed properties
Supports @watch and @watch.ref annotations
Can track nested objects
Provides change detection at both property and path levels
Can be temporarily disabled via unwatch()

Index

Properties

Accessors

isWatching changed changedKeyPaths changedKeys changedTick nested

Methods

get getSafe assumeChanged reset

Properties

`Readonly`id

id: string = ...

Accessors

`Static`isWatching

get isWatching(): boolean
Whether Watcher is enabled in the current transaction

Returns boolean
- Defined in packages/core/src/watcher.ts:159

`Computed`changed

get changed(): boolean
Whether changes have been made

Returns boolean
- Defined in packages/core/src/watcher.ts:193

`Computed`changedKeyPaths

get changedKeyPaths(): ReadonlySet<KeyPath>
The key paths that have changed

Keys of nested objects are included.

Returns ReadonlySet<KeyPath>
- Defined in packages/core/src/watcher.ts:216

`Computed`changedKeys

get changedKeys(): ReadonlySet<KeyPath>
The keys that have changed

Returns ReadonlySet<KeyPath>
Remarks
- Does not include keys of nested objects
- Cleared when reset() is called
- Updated when properties are modified
- Defined in packages/core/src/watcher.ts:206

changedTick

get changedTick(): bigint
The total number of changes processed

Observe this value to react to changes.

Returns bigint
Remarks
- Incremented for each change and each affected key
- Not affected by assumeChanged()
- Reset to 0 when reset() is called
- Defined in packages/core/src/watcher.ts:187

nested

get nested(): ReadonlyMap<KeyPath, Watcher>
Nested watchers

Returns ReadonlyMap<KeyPath, Watcher>
- Defined in packages/core/src/watcher.ts:227

Methods

`Static`get

get<T extends object>(target: T): Watcher
Get a watcher instance for the target object.
Type Parameters
- T extends object
Parameters
- target: T
Returns Watcher
Remarks
- Returns existing instance if one exists for the target
- Creates new instance if none exists
- Instances are cached and garbage collected with their targets
Throws
TypeError if the target is not an object.
- Defined in packages/core/src/watcher.ts:134

`Static`getSafe

getSafe(target: any): null | Watcher
Get a watcher instance for the target object.

Same as Watcher.get but returns null instead of throwing an error.
Parameters
- target: any
Returns null | Watcher
- Defined in packages/core/src/watcher.ts:145

`Action`assumeChanged

assumeChanged(): void
Assume some changes have been made

It only changes changed to true and does not increment changedTick.

Returns void
- Defined in packages/core/src/watcher.ts:257

`Action`reset

reset(): void
Reset the changed state

Returns void
Remarks
- Clears all changed keys
- Resets changedTick to 0
- Clears assumeChanged flag
- Resets all nested watchers
- Defined in packages/core/src/watcher.ts:241