| 1 | import { AsyncIterableX } from './asynciterablex';
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| 2 | import { identityAsync } from '../internal/identity';
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| 3 | import { comparerAsync } from '../internal/comparer';
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| 4 | export class DistinctUntilChangedAsyncIterable extends AsyncIterableX {
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| 5 | constructor(source, keySelector, comparer) {
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| 6 | super();
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| 7 | this._source = source;
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| 8 | this._keySelector = keySelector;
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| 9 | this._comparer = comparer;
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| 10 | }
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| 11 | async *[Symbol.asyncIterator]() {
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| 12 | let currentKey, hasCurrentKey = false;
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| 13 | for await (let item of this._source) {
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| 14 | let key = await this._keySelector(item);
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| 15 | let comparerEquals = false;
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| 16 | if (hasCurrentKey) {
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| 17 | comparerEquals = await this._comparer(currentKey, key);
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| 18 | }
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| 19 | if (!hasCurrentKey || !comparerEquals) {
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| 20 | hasCurrentKey = true;
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| 21 | currentKey = key;
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| 22 | yield item;
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| 23 | }
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| 24 | }
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| 25 | }
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| 26 | }
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| 27 | export function distinctUntilChanged(source, keySelector = identityAsync, comparer = comparerAsync) {
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| 28 | return new DistinctUntilChangedAsyncIterable(source, keySelector, comparer);
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| 29 | }
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| 30 |
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| 31 |
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