publish

연산자(operator) 정의: publish() : ConnectableObservable

Share source and make hot by calling connect.

Examples

Example 1: Connect observable after subscribers

( jsBin | jsFiddle )

//emit value every 1 second
const source = Rx.Observable.interval(1000);
const example = source
  //side effects will be executed once
  .do(() => console.log('Do Something!'))
  //do nothing until connect() is called
  .publish();

/*
  source will not emit values until connect() is called
  output: (after 5s) 
  "Do Something!"
  "Subscriber One: 0"
  "Subscriber Two: 0"
  "Do Something!"
  "Subscriber One: 1"
  "Subscriber Two: 1"
*/
const subscribe = example.subscribe(val => console.log(`Subscriber One: ${val}`));
const subscribeTwo = example.subscribe(val => console.log(`Subscriber Two: ${val}`));

//call connect after 5 seconds, causing source to begin emitting items
setTimeout(() => {
 example.connect(); 
},5000)

Additional Resources

• publish - Official docs

Source Code: https://github.com/ReactiveX/rxjs/blob/master/src/operator/publish.ts