README
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DistinctUntilChanged
DistinctUntilChanged only emits when the current value is different from the last.
The operator only compares emitted items from the source Observable against their immediate predecessors in order to determine whether or not they are distinct.
Example
import _ "github.com/reactivego/rx/generic"
Code:
FromInt(1, 2, 2, 1, 3).DistinctUntilChanged().Println()
Output:
1
2
1
3
Documentation
¶
Overview ¶
DistinctUntilChanged only emits when the current value is different from the last.
The operator only compares emitted items from the source Observable against their immediate predecessors in order to determine whether or not they are distinct.
Example (DistinctUntilChanged) ¶
FromInt(1, 2, 2, 1, 3).DistinctUntilChanged().Println()
Output: 1 2 1 3
Example (DistinctUntilChangedRGBA) ¶
//jig:type RGBA = color.RGBA
c := []color.RGBA{
{R: 1, G: 5, A: 1},
{R: 2, G: 6, A: 2},
{R: 2, G: 6, A: 3}, // this one is NOT distinct => skip
{R: 1, G: 5, A: 4},
{R: 3, G: 3, A: 5},
}
same := func(prev, curr color.RGBA) bool { return prev.R == curr.R && prev.G == curr.G }
FromRGBA(c...).DistinctUntilChanged(same).Println()
Output: {1 5 0 1} {2 6 0 2} {1 5 0 4} {3 3 0 5}
Index ¶
Examples ¶
Constants ¶
const ErrUnsubscribed = RxError("subscriber unsubscribed")
Unsubscribed is the error returned by wait when the Unsubscribe method is called on the subscription.
const TypecastFailed = RxError("typecast failed")
ErrTypecast is delivered to an observer if the generic value cannot be typecast to a specific type.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type IntObserver ¶
IntObserver is a function that gets called whenever the Observable has something to report. The next argument is the item value that is only valid when the done argument is false. When done is true and the err argument is not nil, then the Observable has terminated with an error. When done is true and the err argument is nil, then the Observable has completed normally.
type Observable ¶
type Observable func(Observer, Scheduler, Subscriber)
Observable is a function taking an Observer, Scheduler and Subscriber. Calling it will subscribe the Observer to events from the Observable.
func (Observable) AsObservableInt ¶
func (o Observable) AsObservableInt() ObservableInt
AsObservableInt turns an Observable of interface{} into an ObservableInt. If during observing a typecast fails, the error ErrTypecastToInt will be emitted.
func (Observable) AsObservableRGBA ¶
func (o Observable) AsObservableRGBA() ObservableRGBA
AsObservableRGBA turns an Observable of interface{} into an ObservableRGBA. If during observing a typecast fails, the error ErrTypecastToRGBA will be emitted.
func (Observable) DistinctUntilChanged ¶
func (o Observable) DistinctUntilChanged(equal ...func(interface{}, interface{}) bool) Observable
DistinctUntilChanged only emits when the current value is different from the last.
type ObservableInt ¶
type ObservableInt func(IntObserver, Scheduler, Subscriber)
ObservableInt is a function taking an Observer, Scheduler and Subscriber. Calling it will subscribe the Observer to events from the Observable.
func FromInt ¶
func FromInt(slice ...int) ObservableInt
FromInt creates an ObservableInt from multiple int values passed in.
func (ObservableInt) AsObservable ¶
func (o ObservableInt) AsObservable() Observable
AsObservable turns a typed ObservableInt into an Observable of interface{}.
func (ObservableInt) DistinctUntilChanged ¶
func (o ObservableInt) DistinctUntilChanged(equal ...func(int, int) bool) ObservableInt
DistinctUntilChanged only emits when the current value is different from the last.
func (ObservableInt) Println ¶
func (o ObservableInt) Println(a ...interface{}) error
Println subscribes to the Observable and prints every item to os.Stdout while it waits for completion or error. Returns either the error or nil when the Observable completed normally. Println uses a serial scheduler created with NewScheduler().
type ObservableRGBA ¶
type ObservableRGBA func(RGBAObserver, Scheduler, Subscriber)
ObservableRGBA is a function taking an Observer, Scheduler and Subscriber. Calling it will subscribe the Observer to events from the Observable.
func FromRGBA ¶
func FromRGBA(slice ...color.RGBA) ObservableRGBA
FromRGBA creates an ObservableRGBA from multiple color.RGBA values passed in.
func (ObservableRGBA) AsObservable ¶
func (o ObservableRGBA) AsObservable() Observable
AsObservable turns a typed ObservableRGBA into an Observable of interface{}.
func (ObservableRGBA) DistinctUntilChanged ¶
func (o ObservableRGBA) DistinctUntilChanged(equal ...func(color.RGBA, color.RGBA) bool) ObservableRGBA
DistinctUntilChanged only emits when the current value is different from the last.
func (ObservableRGBA) Println ¶
func (o ObservableRGBA) Println(a ...interface{}) error
Println subscribes to the Observable and prints every item to os.Stdout while it waits for completion or error. Returns either the error or nil when the Observable completed normally. Println uses a serial scheduler created with NewScheduler().
type Observer ¶
Observer is a function that gets called whenever the Observable has something to report. The next argument is the item value that is only valid when the done argument is false. When done is true and the err argument is not nil, then the Observable has terminated with an error. When done is true and the err argument is nil, then the Observable has completed normally.
type RGBAObserver ¶
RGBAObserver is a function that gets called whenever the Observable has something to report. The next argument is the item value that is only valid when the done argument is false. When done is true and the err argument is not nil, then the Observable has terminated with an error. When done is true and the err argument is nil, then the Observable has completed normally.
type Scheduler ¶
Scheduler is used to schedule tasks to support subscribing and observing.
func NewScheduler ¶ added in v0.0.1
func NewScheduler() Scheduler
type Subscriber ¶
type Subscriber interface {
// A Subscriber is also a Subscription.
Subscription
// Add will create and return a new child Subscriber setup in such a way that
// calling Unsubscribe on the parent will also call Unsubscribe on the child.
// Calling the Unsubscribe method on the child will NOT propagate to the
// parent!
Add() Subscriber
// OnUnsubscribe will add the given callback function to the subscriber.
// The callback will be called when either the Unsubscribe of the parent
// or of the subscriber itself is called. If the subscription was already
// canceled, then the callback function will just be called immediately.
OnUnsubscribe(callback func())
// OnWait will register a callback to call when subscription Wait is called.
OnWait(callback func())
// Done will set the error internally and then cancel the subscription by
// calling the Unsubscribe method. A nil value for error indicates success.
Done(err error)
// Error returns the error set by calling the Done(err) method. As long as
// the subscriber is still subscribed Error will return nil.
Error() error
}
Subscriber is a Subscription with management functionality.
func NewSubscriber ¶ added in v0.0.1
func NewSubscriber() Subscriber
New will create and return a new Subscriber.
type Subscription ¶ added in v0.0.1
type Subscription interface {
// Subscribed returns true when the subscription is currently active.
Subscribed() bool
// Unsubscribe will do nothing if the subscription is not active. If the
// state is still active however, it will be changed to canceled.
// Subsequently, it will call Unsubscribe on all child subscriptions added
// through Add, along with all methods added through OnUnsubscribe. When the
// subscription is canceled by calling Unsubscribe a call to the Wait method
// will return the error ErrUnsubscribed.
Unsubscribe()
// Canceled returns true when the subscription state is canceled.
Canceled() bool
// Wait will by default block the calling goroutine and wait for the
// Unsubscribe method to be called on this subscription.
// However, when OnWait was called with a callback wait function it will
// call that instead. Calling Wait on a subscription that has already been
// canceled will return immediately. If the subscriber was canceled by
// calling Unsubscribe, then the error returned is ErrUnsubscribed.
// If the subscriber was terminated by calling Done, then the error
// returned here is the one passed to Done.
Wait() error
}
Subscription is an interface that allows code to monitor and control a subscription it received.
Source Files