Class: Reaction

Defined in: mobx:

Reactions are a special kind of derivations. Several things distinguishes them from normal reactive computations

1. They will always run, whether they are used by other computations or not. This means that they are very suitable for triggering side effects like logging, updating the DOM and making network requests.
2. They are not observable themselves
3. They will always run after any 'normal' derivations
4. They are allowed to change the state and thereby triggering themselves again, as long as they make sure the state propagates to a stable state in a reasonable amount of iterations.

The state machine of a Reaction is as follows:

1. after creating, the reaction should be started by calling runReaction or by scheduling it (see also autorun)
2. the onInvalidate handler should somehow result in a call to this.track(someFunction)
3. all observables accessed in someFunction will be observed by this reaction.
4. as soon as some of the dependencies has changed the Reaction will be rescheduled for another run (after the current mutation or transaction). isScheduled will yield true once a dependency is stale and during this period
5. onInvalidate will be called, and we are back at step 1.

Implements

• IDerivation
• IReactionPublic

Accessors

diffValue

Get Signature

get diffValue(): 0 | 1;

Defined in: mobx:

Returns

0 | 1

Set Signature

set diffValue(newValue: 0 | 1): void;

Defined in: mobx:

Parameters

Parameter	Type
newValue	0 | 1

Returns

void

---

isDisposed

Get Signature

get isDisposed(): boolean;

Defined in: mobx:

Returns

boolean

Set Signature

set isDisposed(newValue: boolean): void;

Defined in: mobx:

Parameters

Parameter	Type
newValue	boolean

Returns

void

---

isRunning

Get Signature

get isRunning(): boolean;

Defined in: mobx:

Returns

boolean

Set Signature

set isRunning(newValue: boolean): void;

Defined in: mobx:

Parameters

Parameter	Type
newValue	boolean

Returns

void

---

isScheduled

Get Signature

get isScheduled(): boolean;

Defined in: mobx:

Returns

boolean

Set Signature

set isScheduled(newValue: boolean): void;

Defined in: mobx:

Parameters

Parameter	Type
newValue	boolean

Returns

void

---

isTrackPending

Get Signature

get isTrackPending(): boolean;

Defined in: mobx:

Returns

boolean

Set Signature

set isTrackPending(newValue: boolean): void;

Defined in: mobx:

Parameters

Parameter	Type
newValue	boolean

Returns

void

Constructors

Constructor

new Reaction(
   name_: string | undefined, 
   onInvalidate_: () => void, 
   errorHandler_?: (error: any, derivation: IDerivation) => void, 
   requiresObservable_?: any): Reaction;

Defined in: mobx:

Parameters

Parameter	Type
name_	string | undefined
onInvalidate_	() => void
errorHandler_?	(error: any, derivation: IDerivation) => void
requiresObservable_?	any

Returns

Reaction

Methods

dispose()

dispose(): void;

Defined in: mobx:

Returns

void

Implementation of

IReactionPublic.dispose

---

getDisposer_()

getDisposer_(abortSignal?: GenericAbortSignal): IReactionDisposer;

Defined in: mobx:

Parameters

Parameter	Type
abortSignal?	GenericAbortSignal

Returns

IReactionDisposer

---

onBecomeStale_()

onBecomeStale_(): void;

Defined in: mobx:

Returns

void

Implementation of

IDerivation.onBecomeStale_

---

reportExceptionInDerivation_()

reportExceptionInDerivation_(error: any): void;

Defined in: mobx:

Parameters

Parameter	Type
error	any

Returns

void

---

runReaction_()

runReaction_(): void;

Defined in: mobx:

internal, use schedule() if you intend to kick off a reaction

Returns

void

---

schedule_()

schedule_(): void;

Defined in: mobx:

Returns

void

---

toString()

toString(): string;

Defined in: mobx:

Returns a string representation of an object.

Returns

string

---

trace()

trace(enterBreakPoint?: boolean): void;

Defined in: mobx:

Parameters

Parameter	Type
enterBreakPoint?	boolean

Returns

void

Implementation of

IReactionPublic.trace

---

track()

track(fn: () => void): void;

Defined in: mobx:

Parameters

Parameter	Type
fn	() => void

Returns

void

Properties

dependenciesState_

dependenciesState_: IDerivationState_;

Defined in: mobx:

Implementation of

IDerivation.dependenciesState_

---

isTracing_

isTracing_: TraceMode;

Defined in: mobx:

Implementation of

IDerivation.isTracing_

---

name_

name_: string;

Defined in: mobx:

Implementation of

IDerivation.name_

---

newObserving_

newObserving_: IObservable[];

Defined in: mobx:

Implementation of

IDerivation.newObserving_

---

observing_

observing_: IObservable[];

Defined in: mobx:

Implementation of

IDerivation.observing_

---

requiresObservable_?

optional requiresObservable_?: any;

Defined in: mobx:

warn if the derivation has no dependencies after creation/update

Implementation of

IDerivation.requiresObservable_

---

runId_

runId_: number;

Defined in: mobx:

Id of the current run of a derivation. Each time the derivation is tracked this number is increased by one. This number is globally unique

Implementation of

IDerivation.runId_

---

unboundDepsCount_

unboundDepsCount_: number;

Defined in: mobx:

amount of dependencies used by the derivation in this run, which has not been bound yet.

Implementation of

IDerivation.unboundDepsCount_