| 1 | import { wrapWithAbort } from './operators/withabort';
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| 2 | import { throwIfAborted } from '../aborterror';
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| 3 | /**
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| 4 | * Returns the only element of an async-iterable sequence that matches the predicate if specified,
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| 5 | * or undefined if no such element exists; this method reports an exception if there is more
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| 6 | * than one element in the async-iterable sequence.
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| 7 | *
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| 8 | * @export
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| 9 | * @template T The type of the elements in the source sequence.
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| 10 | * @param {AsyncIterable<T>} source Source async-iterable sequence.
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| 11 | * @param {OptionalFindOptions<T>} [options] The optional options which includes a predicate for filtering,
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| 12 | * thisArg for predicate binding and an abort signal for cancellation.
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| 13 | * @returns {(Promise<T | undefined>)} A promise with the single element in the async-iterable sequence that satisfies
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| 14 | * the condition in the predicate, or undefined if no such element exists.
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| 15 | */
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| 16 | export async function single(source, options) {
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| 17 | const { ['signal']: signal, ['thisArg']: thisArg, ['predicate']: predicate = async () => true } = options || {};
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| 18 | throwIfAborted(signal);
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| 19 | let result;
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| 20 | let hasResult = false;
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| 21 | let i = 0;
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| 22 | for await (const item of wrapWithAbort(source, signal)) {
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| 23 | if (hasResult && (await predicate.call(thisArg, item, i++, signal))) {
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| 24 | throw new Error('More than one element was found');
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| 25 | }
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| 26 | if (await predicate.call(thisArg, item, i++, signal)) {
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| 27 | result = item;
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| 28 | hasResult = true;
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| 29 | }
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| 30 | }
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| 31 | return result;
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| 32 | }
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| 33 |
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| 34 | //# sourceMappingURL=single.mjs.map
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