Reactive Programming Library for TypeScript
glitch-less & hot Observable only RxJS
npm install rxjs rnjs
import { RN, interval } from 'rnjs'
const a: RN<number> = interval(1000, true); // generate RN
a.subscribe( console.log );
// 0
// 1
// 2
// ...
glitch-less
const a = interval(1000);
const b = a.pipe( map( x => 100 * x ) );
const c = combineLatest( a, b ).pipe( map( ([x, y]) => x + y ) );
c.subscribe( console.log );
// 0
// 1 <-- glitch
// 101
// 102 <-- glitch
// 202
// 203 <-- glitch
// 303
// 304 <-- glitch
// 404
// 405 <-- glitch
// 505
// ...
// RN
const a = interval(1000, true);
const b = a.map( x => 100 * x );
const c = combine( a, b ).map( ([x, y]) => x + y );
c.listen( true, console.log );
// 0
// 101
// 202
// 303
// 404
// 505
// ...
initial value
value property
(like BehaviorSubject in RxJS) import { RN, interval } from 'rnjs'
const a: RN<number> = interval(1000, true).take(8);
a.subscribe( console.log );
// |0---1---2---3---4---5---6---7---|
// ^
setTimeout( () => console.log( a.value ), 3500 ); // 3
// |0---1---2---3---4---5---6---7---|
// ^
setTimeout( () => console.log( a.value ), 5500 ); // 5
hot-RN(Observable) only
compatiblity with RxJS
subscribe API as RxJS
| RN | RxJS v6 |
|---|---|
| interval | interval |
| fromEvent | fromEvent |
| fromPromise | from |
| fromObservable | - |
| manual | BehaviorSubject |
| - | ... |
| RN | RxJS v6 |
|---|---|
| combine | combineLatest |
| merge | merge |
| - | concat |
| - | zip |
| - | ... |
| RN | RxJS v6 |
|---|---|
| auditTime | auditTime |
| delay | delay |
| debounce | debounceTime |
| filter | filter |
| flatMap | flatMap |
| map | map |
| mapTo | mapTo |
| pairwise | pairwise |
| pluck | pluck |
| scan | scan |
| skip | skip |
| skipAlreadyAppeared | distinct |
| skipUnchanged | distinctUntilChanged |
| skipWhile | skipWhile |
| startWith | startWith |
| switchMap | switchMap |
| take | take |
| takeWhile | takeWhile |
| throttle | throttle |
| withLatest | withLatestFrom |
| withTimestamp | timestamp |
| withInitialValue | - |
| - | ... |
import { interval, combine, map } from 'rnjs';
const a = interval(100, true);
// ^
// +--- true --> start immediately
const b = a.pipe( map( x => 100 * x ) );
const c = combine( a, b ).map( ([x, y]) => x + y );
c.subscribe( console.log );
// c.listen( true, console.log );
/* output
0
101
202
303
404
505
...
*/
import { interval, combine } from 'rnjs';
const a = interval(100, false);
// ^
// +--- false --> start manually
const b = a.map( x => 100 * x );
// ^
// +--- all operators can be used without pipe method
const c = combine( a, b ).map( ([x, y]) => x + y );
c.listen( true, console.log );
// ^
// +--- true --> get the first value
a.start(); // start manually
/* output
0 <-- first value
0
101
202
303
404
505
...
*/
a starts before b is generated
--> a.index is not equal to b.index.const a = interval(100, true);
const b = a.map( (sv, si, i) => [100 * sv, si, i] );
b.listen( true, console.log );
/*
[ 0, 0, -1 ]
[ 100, 1, 0 ]
[ 200, 2, 1 ]
[ 300, 3, 2 ]
[ 400, 4, 3 ]
[ 500, 5, 4 ]
[ 600, 6, 5 ]
[ 700, 7, 6 ]
[ 800, 8, 7 ]
[ 900, 9, 8 ]
*/
const a = interval( 100, false );
const b = a.withInitialValue(999)
b.listen( true, console.log );
a.start();
/*
999
0
1
2
3
4
5
6
7
...
*/
/*
interval : 0 |0---1---2---3---4---5---6---7---8---9--
withInitialValue : 999 |0---1---2---3---4---5---6---7---8---9--
*/
const a = interval( 100, false );
const b = a.delay( 50 ).map( x => 100 * x );
const c = merge( a, b );
c.listen( false, console.log );
a.start();
/*
0
0
1
100
2
200
3
300
4
400
5
500
6
600
7
700
*/
/*
interval : 0 |0---1---2---3---4---5---6---7---8---9--
delay : 0 |--0---1---2---3---4---5---6---7---8---9
*/
import { interval } from 'rnjs';
const a = interval(100, true);
const b = a.filter( 0, e => e % 10 < 5 );
// ^
// +--- filter requires initial value
const c = b.debounce(300);
b.listen( false, console.log );
c.listen( false, e => console.log( e, 'debounce') );
/* output
1
2
3
4
4 'debounce'
10
11
12
13
14
14 'debounce'
...
*/
/*
interval : 0 |0--1--2--3--4--5--6--7--8--9--10-11-12-13-14-15-16-17-18-19-
filter : 0 |0--1--2--3--4-----------------10-11-12-13-14----------------
debounce : 0 |---------------------4-----------------------------14-------
*/
const a = interval( 100, false );
const b = a.filter( 0, x => x % 10 < 5 ).throttle( 250 );
b.listen( false, console.log );
a.start();
/*
0
3
10
13
20
23
30
33
40
43
...
*/
/*
interval : 0 |0--1--2--3--4--5--6--7--8--9--10-11-12-13-14-15-16-17-18-19-
filter : 0 |0--1--2--3--4-----------------10-11-12-13-14----------------
throttle : 0 |0--------3--------------------10-------13-------------------
*/
import { interval } from 'rnjs';
const a = interval(100, true);
const b = a.scan( [] as number[], (prev, curr) => {
prev.push( curr );
return prev;
});
a.listen( true, e => console.log('a', e ) );
b.listen( true, e => console.log('b', e ) );
/* output
a 0
b []
a 1
b [ 1 ]
a 2
b [ 1, 2 ]
a 3
b [ 1, 2, 3 ]
*/
import { interval, merge } from 'rnjs';
const a = interval(1000, false);
const b = interval(1000, false);
const c = b.map( e => 100 * e );
const d = merge( a, c );
a.start();
setTimeout(() => { b.start(); }, 500);
d.listen( true, console.log );
/* output
0
0
1
100
2
200
3
300
4
400
5
500
*/
/*
a : 0 |0-------1-------2-------3-------4-------5-------6-------
b : 0 |0------100-----200-----300-----400-----500-----600-----
c : 0 |0---0---1--100--2--200--3--300--4--400--5--500--6--600--
*/
import { interval } from 'rnjs';
interval(100, true).pairwise()
.listen( true, console.log );
/* output
[ 0, 0 ]
[ 0, 1 ]
[ 1, 2 ]
[ 2, 3 ]
[ 3, 4 ]
[ 4, 5 ]
[ 5, 6 ]
[ 6, 7 ]
[ 7, 8 ]
...
*/
/*
interval : 0 |0------1------2------3------4------5------6------
pairwise : [0,0] |[0,0]--[0,1]--[1,2]--[2,3]--[3,4]--[4,5]--[5,6]--
*/
import { interval } from 'rnjs';
const a = interval(100, true);
const b = a.pairwise()
.map( e => ({ prev: e[0], curr: e[1] }) )
.pluck('curr');
b.listen( true, console.log );
/* output
0
1
2
3
...
*/
const a = interval(100, true);
const b = a.take(5);
b.listen( true, console.log );
/*
0
1
2
3
4
*/
const a = interval(100, true);
const b = a.skip( 999, 3 );
// ^
// +--- skip requires initial value
b.listen( true, console.log );
/*
999
3
4
5
6
7
8
9
*/
/*
interval : 0 |0---1---2---3---4---5---6---7---8---9---10--11--12--...
skip : 999 |----------3---1---4---1---5---9---2---6---u---u---...
*/
import { interval } from 'rnjs';
const values = [3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5, 8, 9];
const a = interval(100, false);
const b = a.map( (_sv, _si, i) => values[i] )
.takeWhile( (_sv, _si, i) => 0 <= i && i < values.length )
.skipAlreadyAppeared();
b.listen( false, console.log );
a.start();
/* output
3
1
4
5
9
2
6
8
*/
/*
interval : 0 |0---1---2---3---4---5---6---7---8---9---10--11--12--13--14--...
map : 3 |3---1---4---1---5---9---2---6---5---3---5---8---9---u---u---
takeWhile : 3 |3---1---4---1---5---9---2---6---5---3---5---8---9---
skipAlreadyAppeared : 3 |3---1---4-------5---9---2---6---------------8-------
*/
const values = [3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5, 8, 9];
const a = interval(100, true);
const b = a.map( (_sv, _si, i) => values[i] )
.takeWhile( (_sv, _si, i) => 0 <= i && i < values.length )
.skipAlreadyAppeared();
b.listen( false, console.log );
/* output
3
1
4
5
9
2
6
8
*/
/*
interval : 0 |0---1---2---3---4---5---6---7---8---9---10--11--12--13--14--...
map : ud |3---1---4---1---5---9---2---6---5---3---5---8---9---u---u---
takeWhile : ud |3---1---4---1---5---9---2---6---5---3---5---8---9---
skipAlreadyAppeared : ud |3---1---4-------5---9---2---6---------------8-------
*/
const values = [3, 3, 3, 1, 4, 1, 5, 9, 9, 9, 2, 6];
const a = interval(100, true);
const b = a.map( (_sv, _si, i) => values[i] )
.takeWhile( (_sv, _si, i) => 0 <= i && i < values.length )
.skipUnchanged();
b.listen( false, console.log );
/*
3
1
4
1
5
9
2
6
*/
/*
interval : 0 |0---1---2---3---4---5---6---7---8---9---10--11--12--...
map : ud |--3---3---3---1---4---1---5---9---2---6---u---u---...
takeWhile : ud |--3---3---3---1---4---1---5---9---2---6---
skipUnchanged : ud |--3-----------1---4---1---5---9---2---6---
*/
const a = interval(300, true);
const b = interval(100, true);
const c = a.withLatest( b );
c.listen( true, console.log );
/*
[ 0, 0 ]
[ 1, 2 ]
[ 2, 5 ]
[ 3, 8 ]
[ 4, 11 ]
[ 5, 14 ]
[ 6, 17 ]
[ 7, 20 ]
[ 8, 23 ]
[ 9, 26 ]
[ 10, 29 ]
*/
/*
a : 0 |0-----------1-----------2-----------3-----------4----...
b : 0 |0---1---2---3---4---5---6---7---8---9---10--11--12--...
c : [0,0] |----------[1,2]-------[2,5]-------[3,8]-------[4,11]--...
*/
const a = interval(300, true);
const b = a.withTimestamp();
b.listen( true, console.log );
/*
[ 0, 1544903873595 ]
[ 1, 1544903873896 ]
[ 2, 1544903874195 ]
[ 3, 1544903874497 ]
[ 4, 1544903874797 ]
*/
const a = interval( 500, true );
const b = a.valueIs(3);
combine(a, b).listen( true, console.log )
/*
[ 0, false ]
[ 1, false ]
[ 2, false ]
[ 3, true ]
[ 4, false ]
[ 5, false ]
...
*/
const a = interval( 500, true );
const b = a.valueIsNot(3);
combine(a, b).listen( true, console.log )
/*
[ 0, true ]
[ 1, true ]
[ 2, true ]
[ 3, false ]
[ 4, true ]
[ 5, true ]
...
*/
const a = interval(1000, true);
const b = a.switchMap( x => interval(300, true).mapTo(x) );
b.listen( true, console.log );
/*
0
0
0
0
1
1
1
1
2
2
*/
/*
interval : 0 |0---------1---------2---------...
(mapped-1) : 0 |0--0--0--0--0--0--0--0--0--0--...
(mapped-2) : 0 |1--1--1--1--1--1--1-...
(mapped-3) : 0 |2--2--2--2...
...
--- switchMap & mapTo ---
[0,0] |0--0--0--01--1--1--12--2--2--2...
*/
const a = interval(1000, true);
const b = a.flatMap( x => interval(300, true).mapTo(x) );
b.listen( true, console.log );
/*
0
0
0
0
1
0
1
0
1
0
1
2
0
1
2
0
1
2
0
1
*/
/*
interval : 0 |0---------1---------2---------...
(mapped-1) : 0 |0--0--0--0--0--0--0--0--0--0--...
(mapped-2) : 0 |1--1--1--1--1--1--1-...
(mapped-3) : 0 |2--2--2--2...
...
--- flatMap & mapTo ---
[0,0] |0--0--0--01-01-01-012012012012012012012012012
*/
const counter = interval( 500, true );
const a = counter.map( x => x % 2 === 0 );
const b = counter.map( x => x % 3 === 0 );
counter.listen( true, console.log );
every(a, b).listen( true, console.log );
/*
0
true
1
false
2
false
3
false
4
false
5
false
6
true
7
false
counter : 0 |0---1---2---3---4---5---6---7---...
a : T |T---F---T---F---T---F---T---F---...
b : T |T---F---F---T---F---F---T---F---...
every : T |T---F---F---F---F---F---T---F---...
const counter = interval( 500, true );
const a = counter.map( x => x % 2 === 0 );
const b = counter.map( x => x % 3 === 0 );
counter.listen( true, console.log );
some(a, b).listen( true, console.log );
/*
0
true
1
false
2
true
3
true
4
true
5
false
6
true
7
false
...
counter : 0 |0---1---2---3---4---5---6---7---...
a : T |T---F---T---F---T---F---T---F---...
b : T |T---F---F---T---F---F---T---F---...
some : T |T---F---T---T---T---F---T---F---...
const a = interval( 500, true ).take( 5 );
const pr = a.toPromise();
a.listen( true, console.log );
pr.then( v => console.log('resolve', v ) );
/*
0
1
2
3
4
resolve 4
*/
const a = interval( 500, true ).take( 5 );
const ob = a.toObservable();
a.listen( true, v => console.log('listen', v) );
ob.subscribe( v => console.log('subscribe', v ) );
/*
listen 0
subscribe 0
subscribe 1
listen 1
subscribe 2
listen 2
subscribe 3
listen 3
subscribe 4
listen 4
*/
const a = interval( 1000, true ).take( 5 );
a.listen( true, console.log );
setTimeout( () => a.once().then( v => console.log('once', v ) ), 2500 );
/*
0
1
2
3
once 3
4
interval : 0 |0-----1-----2-----3-----4-----
^ ^
| |
| +---once resolves
+---once is called
*/
FAQs
Reactive Programming Library for TypeScript/JavaScript
The npm package rnjs receives a total of 4 weekly downloads. As such, rnjs popularity was classified as not popular.
We found that rnjs demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 1 open source maintainer collaborating on the project.
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