work.suroh.tk/node_modules/rxjs/operators/single.js

93 lines
3.3 KiB
JavaScript

"use strict";
var __extends = (this && this.__extends) || function (d, b) {
for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
function __() { this.constructor = d; }
d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
};
var Subscriber_1 = require('../Subscriber');
var EmptyError_1 = require('../util/EmptyError');
/**
* Returns an Observable that emits the single item emitted by the source Observable that matches a specified
* predicate, if that Observable emits one such item. If the source Observable emits more than one such item or no
* such items, notify of an IllegalArgumentException or NoSuchElementException respectively.
*
* <img src="./img/single.png" width="100%">
*
* @throws {EmptyError} Delivers an EmptyError to the Observer's `error`
* callback if the Observable completes before any `next` notification was sent.
* @param {Function} predicate - A predicate function to evaluate items emitted by the source Observable.
* @return {Observable<T>} An Observable that emits the single item emitted by the source Observable that matches
* the predicate.
.
* @method single
* @owner Observable
*/
function single(predicate) {
return function (source) { return source.lift(new SingleOperator(predicate, source)); };
}
exports.single = single;
var SingleOperator = (function () {
function SingleOperator(predicate, source) {
this.predicate = predicate;
this.source = source;
}
SingleOperator.prototype.call = function (subscriber, source) {
return source.subscribe(new SingleSubscriber(subscriber, this.predicate, this.source));
};
return SingleOperator;
}());
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
var SingleSubscriber = (function (_super) {
__extends(SingleSubscriber, _super);
function SingleSubscriber(destination, predicate, source) {
_super.call(this, destination);
this.predicate = predicate;
this.source = source;
this.seenValue = false;
this.index = 0;
}
SingleSubscriber.prototype.applySingleValue = function (value) {
if (this.seenValue) {
this.destination.error('Sequence contains more than one element');
}
else {
this.seenValue = true;
this.singleValue = value;
}
};
SingleSubscriber.prototype._next = function (value) {
var index = this.index++;
if (this.predicate) {
this.tryNext(value, index);
}
else {
this.applySingleValue(value);
}
};
SingleSubscriber.prototype.tryNext = function (value, index) {
try {
if (this.predicate(value, index, this.source)) {
this.applySingleValue(value);
}
}
catch (err) {
this.destination.error(err);
}
};
SingleSubscriber.prototype._complete = function () {
var destination = this.destination;
if (this.index > 0) {
destination.next(this.seenValue ? this.singleValue : undefined);
destination.complete();
}
else {
destination.error(new EmptyError_1.EmptyError);
}
};
return SingleSubscriber;
}(Subscriber_1.Subscriber));
//# sourceMappingURL=single.js.map