44 lines
792 B
JavaScript
44 lines
792 B
JavaScript
|
const { ReplaySubject } = require('rxjs');
|
||
|
|
const { map, scan } = require('rxjs/operators');
|
||
|
|
|
||
|
|
const { exhaustMap, takeLast, take } = require('rxjs/operators');
|
||
|
|
|
||
|
|
let _scan = scan((acc, curr) => {
|
||
|
|
acc.push(curr);
|
||
|
|
if (acc.length > 4) {
|
||
|
|
acc.shift();
|
||
|
|
}
|
||
|
|
return acc;
|
||
|
|
}, [])
|
||
|
|
|
||
|
|
let _average = map(arr => arr.reduce((acc, current) => acc + current, 0) / arr.length)
|
||
|
|
|
||
|
|
let sub = new ReplaySubject();
|
||
|
|
sub.next(1)
|
||
|
|
sub.next(2)
|
||
|
|
sub.next(3)
|
||
|
|
sub.next(4)
|
||
|
|
|
||
|
|
// sub.pipe(_scan, _average).subscribe((v) => {
|
||
|
|
sub.pipe(takeLast(2)).subscribe((v) => {
|
||
|
|
console.log("got value " + v)
|
||
|
|
})
|
||
|
|
|
||
|
|
// result:
|
||
|
|
// got value 1
|
||
|
|
// got value 1.5
|
||
|
|
// got value 2
|
||
|
|
// got value 2.5
|
||
|
|
|
||
|
|
// wanted result:
|
||
|
|
// got value 2.5
|
||
|
|
|
||
|
|
console.dir("---------")
|
||
|
|
|
||
|
|
sub.next(5)
|
||
|
|
sub.next(6)
|
||
|
|
|
||
|
|
// expected afterwards
|
||
|
|
// got value 3.5
|
||
|
|
// got value 4.5
|