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