callbag-take-until

- Emits the values emitted by the source Callbag until a notifier Callbag emits a value.
- Works on either pullable or listenable sources.
- NOTE: if the notifier immediately completes without emitting any data (i.e.: callbag-empty) the source callbag will NOT be terminated.

npm install callbag-take-until

Examples

$3

Drag and drop:
Demo Here

``js
import forEach from 'callbag-for-each';
import fromEvent from 'callbag-from-event';
import map from 'callbag-map';
import pipe from 'callbag-pipe';
import switchMap from 'callbag-switch-map';
import takeUntil from 'callbag-take-until';

const getCoords = downEvt => moveEvt => {
moveEvt.preventDefault();
return {
left: moveEvt.clientX - downEvt.offsetX,
top: moveEvt.clientY - downEvt.offsetY
};
};

const ball = document.querySelector('.drag-ball');
const mouseDown$ = fromEvent(ball, 'mousedown');
const mouseUp$ = fromEvent(ball, 'mouseup');
const mouseMove$ = fromEvent(document, 'mousemove');

pipe(
mouseDown$,
switchMap(downEvt =>
pipe(
mouseMove$,
map(getCoords(downEvt)),
takeUntil(mouseUp$)
)
),
forEach(({ left, top }) => {
ball.style.left = ${left}px;
ball.style.top = ${top}px;
})
);
`

Listenable source that will not be terminated


`js
const empty = require('callbag-empty');
const interval = require('callbag-interval');
const pipe = require('callbag-pipe');
const subscribe = require('callbag-subscribe');
const takeUntil = require('callbag-take-until');

pipe(
interval(500),
takeUntil(empty()),
subscribe({
next(v) {
console.log('value', v);
},
complete() {
console.log('done'); // won't ever be called
}
})
);
`

$3

Immediatelly "unsubscribe" from the source:

`js
const forEach = require('callbag-for-each');
const fromIter = require('callbag-from-iter');
const pipe = require('callbag-pipe');
const takeUntil = require('callbag-take-until');

pipe(
fromIter([1, 2, 3]),
takeUntil(fromIter('a')),
forEach((x) => {
console.log(x); // void (immediately stops pulling)
})
);
``