initial commit - far from runnable

node_modules/rxjs/src/internal/operators/findIndex.ts

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+import { Observable } from '../Observable';
+import { Falsy, OperatorFunction } from '../types';
+import { operate } from '../util/lift';
+import { createFind } from './find';
+
+export function findIndex<T>(predicate: BooleanConstructor): OperatorFunction<T, T extends Falsy ? -1 : number>;
+/** @deprecated Use a closure instead of a `thisArg`. Signatures accepting a `thisArg` will be removed in v8. */
+export function findIndex<T>(predicate: BooleanConstructor, thisArg: any): OperatorFunction<T, T extends Falsy ? -1 : number>;
+/** @deprecated Use a closure instead of a `thisArg`. Signatures accepting a `thisArg` will be removed in v8. */
+export function findIndex<T, A>(
+  predicate: (this: A, value: T, index: number, source: Observable<T>) => boolean,
+  thisArg: A
+): OperatorFunction<T, number>;
+export function findIndex<T>(predicate: (value: T, index: number, source: Observable<T>) => boolean): OperatorFunction<T, number>;
+
+/**
+ * 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>
+ *
+ * ![](findIndex.png)
+ *
+ * `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
+ *
+ * Emit the index of first click that happens on a DIV element
+ *
+ * ```ts
+ * import { fromEvent, findIndex } from 'rxjs';
+ *
+ * const div = document.createElement('div');
+ * div.style.cssText = 'width: 200px; height: 200px; background: #09c;';
+ * document.body.appendChild(div);
+ *
+ * const clicks = fromEvent(document, 'click');
+ * const result = clicks.pipe(findIndex(ev => (<HTMLElement>ev.target).tagName === 'DIV'));
+ * result.subscribe(x => console.log(x));
+ * ```
+ *
+ * @see {@link filter}
+ * @see {@link find}
+ * @see {@link first}
+ * @see {@link take}
+ *
+ * @param predicate A function called with each item to test for condition matching.
+ * @param thisArg An optional argument to determine the value of `this` in the
+ * `predicate` function.
+ * @return A function that returns an Observable that emits the index of the
+ * first item that matches the condition.
+ */
+export function findIndex<T>(
+  predicate: (value: T, index: number, source: Observable<T>) => boolean,
+  thisArg?: any
+): OperatorFunction<T, number> {
+  return operate(createFind(predicate, thisArg, 'index'));
+}