| import { FindValueOperator } from '../operators/find'; |
| /** |
| * Emits only the index of the first value emitted by the source Observable that |
| * meets some condition. |
| * |
| * <span class="informal">It's like {@link find}, but emits the index of the |
| * found value, not the value itself.</span> |
| * |
| * <img src="./img/findIndex.png" width="100%"> |
| * |
| * `findIndex` searches for the first item in the source Observable that matches |
| * the specified condition embodied by the `predicate`, and returns the |
| * (zero-based) index of the first occurrence in the source. Unlike |
| * {@link first}, the `predicate` is required in `findIndex`, and does not emit |
| * an error if a valid value is not found. |
| * |
| * @example <caption>Emit the index of first click that happens on a DIV element</caption> |
| * var clicks = Rx.Observable.fromEvent(document, 'click'); |
| * var result = clicks.findIndex(ev => ev.target.tagName === 'DIV'); |
| * result.subscribe(x => console.log(x)); |
| * |
| * @see {@link filter} |
| * @see {@link find} |
| * @see {@link first} |
| * @see {@link take} |
| * |
| * @param {function(value: T, index: number, source: Observable<T>): boolean} predicate |
| * A function called with each item to test for condition matching. |
| * @param {any} [thisArg] An optional argument to determine the value of `this` |
| * in the `predicate` function. |
| * @return {Observable} An Observable of the index of the first item that |
| * matches the condition. |
| * @method find |
| * @owner Observable |
| */ |
| export function findIndex(predicate, thisArg) { |
| return (source) => source.lift(new FindValueOperator(predicate, source, true, thisArg)); |
| } |
| //# sourceMappingURL=findIndex.js.map |
