22 lines
857 B
JavaScript
22 lines
857 B
JavaScript
import { identity } from '../util/identity';
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import { operate } from '../util/lift';
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import { createOperatorSubscriber } from './OperatorSubscriber';
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export function distinctUntilChanged(comparator, keySelector = identity) {
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comparator = comparator !== null && comparator !== void 0 ? comparator : defaultCompare;
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return operate((source, subscriber) => {
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let previousKey;
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let first = true;
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source.subscribe(createOperatorSubscriber(subscriber, (value) => {
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const currentKey = keySelector(value);
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if (first || !comparator(previousKey, currentKey)) {
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first = false;
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previousKey = currentKey;
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subscriber.next(value);
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}
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}));
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});
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}
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function defaultCompare(a, b) {
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return a === b;
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}
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//# sourceMappingURL=distinctUntilChanged.js.map
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