hugoWebsite/node_modules/rxjs/dist/esm/internal/operators/single.js

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2022-10-29 00:20:35 +02:00
import { EmptyError } from '../util/EmptyError';
import { SequenceError } from '../util/SequenceError';
import { NotFoundError } from '../util/NotFoundError';
import { operate } from '../util/lift';
import { createOperatorSubscriber } from './OperatorSubscriber';
export function single(predicate) {
return operate((source, subscriber) => {
let hasValue = false;
let singleValue;
let seenValue = false;
let index = 0;
source.subscribe(createOperatorSubscriber(subscriber, (value) => {
seenValue = true;
if (!predicate || predicate(value, index++, source)) {
hasValue && subscriber.error(new SequenceError('Too many matching values'));
hasValue = true;
singleValue = value;
}
}, () => {
if (hasValue) {
subscriber.next(singleValue);
subscriber.complete();
}
else {
subscriber.error(seenValue ? new NotFoundError('No matching values') : new EmptyError());
}
}));
});
}
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