[RxJS] Asyncsubject

Asyncsubject emit The last value of a sequence only if the sequence completed. This value was then cached Forever, and any other Observer that subscribes after the value have been emmitted would receive it right away.

Asyncsubject is convenient for asynchronous operations that return a single value, such as Ajax requests.

varSubject =NewRx.asyncsubject ();varDelayedrange = Rx.Observable.range (0,5). Delay ( +);d elayedrange.subscribe (subject);//----[0,1,2,3,4]|//Asyncsubject//----4|Subject.subscribe (function OnNext (item) {Console.log ('Value:', item); }, function OnError (err) {Console.log ('Error:', err); }, Function oncompleted () {Console.log ('completed.'); })/*" Value:" 4 "completed."*/

A More useful example:

functiongetproducts (URL) {varsubject; returnRx.Observable.create (function(Observer) {//If first time, then create Asyncsubject    if(!subject) {Subject=NewRx.asyncsubject (); //Subscribe to SubjectRx.DOM.get (URL). Subscribe (subject); }    //If subject already exists, then just subscribe observer    returnSUBJECT.SUBSCRIBE (Observer); })}varProducts = getproducts ('/products ');//Would trigger request and receive the response when readProducts.subscribe (functionOnNext (Result) {Console.log (' result 1: '), Result.response)},functionOnError (Error) {Console.log (' error '), error)});//Would receive the result immediately because it is cachedSetTimeout (function() {Products.subscribe (functionOnNext (Result) {Console.log (' Result 2: '), Result.response)},functionOnError (Error) {Console.log (' error '), Error)} )}, 5000)

[RxJS] Asyncsubject