1 | import { Operator } from '../Operator';
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2 | import { Subscriber } from '../Subscriber';
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3 | import { OperatorFunction } from '../types';
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4 | /**
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5 | * Applies a given `project` function to each value emitted by the source
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6 | * Observable, and emits the resulting values as an Observable.
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7 | *
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8 | * <span class="informal">Like [Array.prototype.map()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map),
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9 | * it passes each source value through a transformation function to get
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10 | * corresponding output values.</span>
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11 | *
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12 | * ![](map.png)
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13 | *
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14 | * Similar to the well known `Array.prototype.map` function, this operator
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15 | * applies a projection to each value and emits that projection in the output
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16 | * Observable.
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17 | *
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18 | * ## Example
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19 | * Map every click to the clientX position of that click
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20 | * ```ts
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21 | * import { fromEvent } from 'rxjs';
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22 | * import { map } from 'rxjs/operators';
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23 | *
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24 | * const clicks = fromEvent(document, 'click');
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25 | * const positions = clicks.pipe(map(ev => ev.clientX));
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26 | * positions.subscribe(x => console.log(x));
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27 | * ```
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28 | *
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29 | * @see {@link mapTo}
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30 | * @see {@link pluck}
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31 | *
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32 | * @param {function(value: T, index: number): R} project The function to apply
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33 | * to each `value` emitted by the source Observable. The `index` parameter is
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34 | * the number `i` for the i-th emission that has happened since the
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35 | * subscription, starting from the number `0`.
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36 | * @param {any} [thisArg] An optional argument to define what `this` is in the
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37 | * `project` function.
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38 | * @return {Observable<R>} An Observable that emits the values from the source
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39 | * Observable transformed by the given `project` function.
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40 | * @method map
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41 | * @owner Observable
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42 | */
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43 | export declare function map<T, R>(project: (value: T, index: number) => R, thisArg?: any): OperatorFunction<T, R>;
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44 | export declare class MapOperator<T, R> implements Operator<T, R> {
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45 | private project;
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46 | private thisArg;
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47 | constructor(project: (value: T, index: number) => R, thisArg: any);
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48 | call(subscriber: Subscriber<R>, source: any): any;
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49 | }
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