wishthis/node_modules/rxjs/dist/esm/internal/observable/combineLatest.js
2022-06-08 12:36:39 +02:00

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2.5 KiB
JavaScript

import { Observable } from '../Observable';
import { argsArgArrayOrObject } from '../util/argsArgArrayOrObject';
import { from } from './from';
import { identity } from '../util/identity';
import { mapOneOrManyArgs } from '../util/mapOneOrManyArgs';
import { popResultSelector, popScheduler } from '../util/args';
import { createObject } from '../util/createObject';
import { createOperatorSubscriber } from '../operators/OperatorSubscriber';
import { executeSchedule } from '../util/executeSchedule';
export function combineLatest(...args) {
const scheduler = popScheduler(args);
const resultSelector = popResultSelector(args);
const { args: observables, keys } = argsArgArrayOrObject(args);
if (observables.length === 0) {
return from([], scheduler);
}
const result = new Observable(combineLatestInit(observables, scheduler, keys
?
(values) => createObject(keys, values)
:
identity));
return resultSelector ? result.pipe(mapOneOrManyArgs(resultSelector)) : result;
}
export function combineLatestInit(observables, scheduler, valueTransform = identity) {
return (subscriber) => {
maybeSchedule(scheduler, () => {
const { length } = observables;
const values = new Array(length);
let active = length;
let remainingFirstValues = length;
for (let i = 0; i < length; i++) {
maybeSchedule(scheduler, () => {
const source = from(observables[i], scheduler);
let hasFirstValue = false;
source.subscribe(createOperatorSubscriber(subscriber, (value) => {
values[i] = value;
if (!hasFirstValue) {
hasFirstValue = true;
remainingFirstValues--;
}
if (!remainingFirstValues) {
subscriber.next(valueTransform(values.slice()));
}
}, () => {
if (!--active) {
subscriber.complete();
}
}));
}, subscriber);
}
}, subscriber);
};
}
function maybeSchedule(scheduler, execute, subscription) {
if (scheduler) {
executeSchedule(subscription, scheduler, execute);
}
else {
execute();
}
}
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