@reactivex/rxjs/dist-compat/cjs/src/internal/operators/last.js

Reactive Extensions for modern JavaScript

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
var EmptyError_1 = require("../util/EmptyError");
var filter_1 = require("./filter");
var takeLast_1 = require("./takeLast");
var throwIfEmpty_1 = require("./throwIfEmpty");
var defaultIfEmpty_1 = require("./defaultIfEmpty");
var identity_1 = require("../util/identity");
/* tslint:enable:max-line-length */
/**
 * Returns an Observable that emits only the last item emitted by the source Observable.
 * It optionally takes a predicate function as a parameter, in which case, rather than emitting
 * the last item from the source Observable, the resulting Observable will emit the last item
 * from the source Observable that satisfies the predicate.
 *
 * ![](last.png)
 *
 * @throws {EmptyError} Delivers an EmptyError to the Observer's `error`
 * callback if the Observable completes before any `next` notification was sent.
 * @param {function} [predicate] - The condition any source emitted item has to satisfy.
 * @param {any} [defaultValue] - An optional default value to provide if last
 * predicate isn't met or no values were emitted.
 * @return {Observable} An Observable that emits only the last item satisfying the given condition
 * from the source, or an NoSuchElementException if no such items are emitted.
 * @throws - Throws if no items that match the predicate are emitted by the source Observable.
 */
function last(predicate, defaultValue) {
    var hasDefaultValue = arguments.length >= 2;
    return function (source) { return source.pipe(predicate ? filter_1.filter(function (v, i) { return predicate(v, i, source); }) : identity_1.identity, takeLast_1.takeLast(1), hasDefaultValue ? defaultIfEmpty_1.defaultIfEmpty(defaultValue) : throwIfEmpty_1.throwIfEmpty(function () { return new EmptyError_1.EmptyError(); })); };
}
exports.last = last;
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