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- import { OperatorFunction } from '../types';
- /**
- * Groups pairs of consecutive emissions together and emits them as an array of
- * two values.
- *
- * <span class="informal">Puts the current value and previous value together as
- * an array, and emits that.</span>
- *
- * 
- *
- * The Nth emission from the source Observable will cause the output Observable
- * to emit an array [(N-1)th, Nth] of the previous and the current value, as a
- * pair. For this reason, `pairwise` emits on the second and subsequent
- * emissions from the source Observable, but not on the first emission, because
- * there is no previous value in that case.
- *
- * ## Example
- *
- * On every click (starting from the second), emit the relative distance to the previous click
- *
- * ```ts
- * import { fromEvent, pairwise, map } from 'rxjs';
- *
- * const clicks = fromEvent<PointerEvent>(document, 'click');
- * const pairs = clicks.pipe(pairwise());
- * const distance = pairs.pipe(
- * map(([first, second]) => {
- * const x0 = first.clientX;
- * const y0 = first.clientY;
- * const x1 = second.clientX;
- * const y1 = second.clientY;
- * return Math.sqrt(Math.pow(x0 - x1, 2) + Math.pow(y0 - y1, 2));
- * })
- * );
- *
- * distance.subscribe(x => console.log(x));
- * ```
- *
- * @see {@link buffer}
- * @see {@link bufferCount}
- *
- * @return A function that returns an Observable of pairs (as arrays) of
- * consecutive values from the source Observable.
- */
- export declare function pairwise<T>(): OperatorFunction<T, [T, T]>;
- //# sourceMappingURL=pairwise.d.ts.map
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