30 lines
1.1 KiB
JavaScript
30 lines
1.1 KiB
JavaScript
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import { EmptyError } from '../util/EmptyError';
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import { SequenceError } from '../util/SequenceError';
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import { NotFoundError } from '../util/NotFoundError';
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import { operate } from '../util/lift';
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import { createOperatorSubscriber } from './OperatorSubscriber';
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export function single(predicate) {
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return operate((source, subscriber) => {
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let hasValue = false;
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let singleValue;
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let seenValue = false;
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let index = 0;
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source.subscribe(createOperatorSubscriber(subscriber, (value) => {
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seenValue = true;
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if (!predicate || predicate(value, index++, source)) {
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hasValue && subscriber.error(new SequenceError('Too many matching values'));
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hasValue = true;
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singleValue = value;
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}
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}, () => {
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if (hasValue) {
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subscriber.next(singleValue);
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subscriber.complete();
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}
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else {
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subscriber.error(seenValue ? new NotFoundError('No matching values') : new EmptyError());
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}
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}));
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});
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}
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//# sourceMappingURL=single.js.map
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