Computed<T> class

Auto compute values from some observable by async update function

Inheritance

• Object
• ObservableBase<T>
• Computed

Implementers

• Commission

Constructors

Computed(FutureOr<T> calculator(), {int rateLimit = 0, void onError(Object error, StackTrace stack)?, Validator? validator})

Create a observable that calculate value base on other observables

Properties

calculator → FutureOr<T> Function()

Function used to calculate value

final

dependCount → int

Number of observable which this object depend on

no setter

error → String?

Error message if value invalid, otherwise is null

no setter, inherited

hashCode → int

The hash code for this object.

no setter, inherited

hasListener → bool

Check there are listeners on this observable

no setter, inherited

hasValidator → bool

Check has using validate value

no setter, inherited

isPaused → bool

Current status rebuild value is pause or not

no setter

modified → bool

Check value has updated

no setter, inherited

oldValue → T

The old value if has change

no setter, override

onError → (void Function(Object error, StackTrace stack)?)

Function called if there are error in procession calculator

final

peek → T

The current value but ignore check depend on in Computed context

no setter, override

rateLimit ↔ int

Only notify change and rebuild after a number period (millisecond)

getter/setter pair

rebuildCount → int

Number times of calculator was called

no setter

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

stream → Stream<T>

Create a broadcast stream to listen value changes.

no setter, inherited

subcriptions → List<Subscription>

The current subscription listen on to update computed

no setter

valid → bool

Validate status

no setter, inherited

validStatus → ValidateStatus

Get current status of validating process

no setter, inherited

value → T

The current value, if value called in a computed context, it will set Computed is depend on this

no setter, inherited

Methods

call() → T

inherited

changed(Function callback) → Subscription

Listen on value changed then run callback

override

dispose() → void

Remember close a computed if you don't need it to avoid it auto rebuild

override

listen(Function callback) → Subscription

Listen on value changed then run callback, it also run callback in first time

override

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

notify() → void

Notify to observers are listen on this observable

inherited

pause() → void

Temporary pause rebuild value if there are an observable changed

resume() → void

Resume and rebuild value after paused

setError(String? msg) → void

Manual set error, used to update error message by validate outsite

inherited

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited

Static Methods

ignoreDependencies<T>(T callback()) → T

Ignore dependency all observables in callback for current Computed

task<T>(List<ObservableBase> depends, T callback()) → Computed<T>

Run a task depends on specific observables

version(List<ObservableBase> depends) → Computed<int>

Create a computed used to listen on specific observable