[RxJS] Subject:an Observable and Observer hybrid

This lesson teaches what a Subject is simply a hybrid of Observable and Observer which can act as a bridge between the Source Observable and multiple observers, effectively making it possible for multiple observers to share the same OBSERVAB Le execution.

varObservable = Rx.Observable.interval ( +). Take (5);varObservera ={next:function (x) {Console.log ('A Next'+x); }, Error:function (err) {Console.log ('A Error'+err); }, Complete:function () {Console.log ('A Done'); },};varObserverb ={next:function (x) {Console.log ('B Next'+x); }, Error:function (err) {Console.log ('B Error'+err); }, Complete:function () {Console.log ('B Done'); },};observable.subscribe (Observera); SetTimeout (()={observable.subscribe (observerb); }, -)

In the code above, we have both ' observers ', because we call subscribe twice:

Observable.scbscribe (Observera); Observable.scbscribe (Observerb);

If we want to has one observer, so we need to call subscribe only once.

For that we can build a bridgeobservers, which would loop though the observers:

ConstObservable = Rx.Observable.interval ( +). Take (5);ConstObservera ={next:function (x) {Console.log ("A Next"+x)}, Error:function (x) {Console.error ("A Error"+x)}, Complete:function () {Console.log ("A Done")  },};ConstObserverb ={next:function (x) {Console.log ("B Next"+x)}, Error:function (x) {Console.error ("B Error"+x)}, Complete:function () {Console.log ("B Done")  },};Const bridgeobservers={next:function (x) { This. Observers.foreach (o=O.next (x))}, Error:function (x) { This. Observers.foreach (o=o.error (x))}, Complete:function () { This. Observers.foreach (o=o.complete ())}, observers: [], ADDOBSERVER:FUNCTION (Observer) { This. OBSERVERS.PUSH (Observer)}};observable.subscribe (Bridgeobservers); Bridgeobservers.addobserver (Observera); SetTimeout (function () {bridgeobservers.addobserver (observerb);}, -)

And this partten:

Observable.subscribe (bridgeobservers); Bridgeobservers.addobserver (Observera); Birdegeobservers.subscribe (Observera)

is actually ' subject ' partten, works both as Observer and Observable.

Subject:

ConstObservable = Rx.Observable.interval ( +). Take (5);ConstObservera ={next:function (x) {Console.log ("A Next"+x)}, Error:function (x) {Console.error ("A Error"+x)}, Complete:function () {Console.log ("A Done")  },};ConstObserverb ={next:function (x) {Console.log ("B Next"+x)}, Error:function (x) {Console.error ("B Error"+x)}, Complete:function () {Console.log ("B Done")  },}; const subject = new  rx.subject (); /*Const Bridgeobservers = {next:function (x) {This.observers.forEach (o = O.next (x))}, Error:funct      Ion (x) {This.observers.forEach (o = o.error (x))}, Complete:function () {This.observers.forEach ( o = = O.complete ())}, observers: [], SUBSCRIBE:FUNCTION (Observer) {THIS.OBSERVERS.PUSH (Observer)}};*/ observable.subscribe (subject); Subject.subscribe (Observera); //Bridgeobservers.subscribe (Observera);setTimeout (function () { subject.subscribe (observerb); //Bridgeobservers.subscribe (observerb);}, -)

In the end, Observera and OBSERVERB share one single observer.

[RxJS] Subject:an Observable and Observer hybrid