@reactivex/ix-es5-esm/asynciterable/fromeventpattern.js

The Interactive Extensions for JavaScript

import { __asyncGenerator, __await, __generator, __read, __spreadArray } from "tslib";
import { memoize } from './operators/memoize.js';
import { identity } from '../util/identity.js';
import { isFunction } from '../util/isiterable.js';
import { AsyncSink } from './asyncsink.js';
var isArray = Array.isArray;
function callOrApply(fn, args) {
    return isArray(args) ? fn.apply(void 0, __spreadArray([], __read(args), false)) : fn(args);
}
/**
 * Creates async-iterable from an event emitter by adding handlers for both listening and unsubscribing from events.
 *
 * @template TSource The type of elements in the event emitter.
 * @param {(handler: (...args: any[]) => void) => void} addHandler The function to add a listener to the source.
 * @param {(handler: (...args: any[]) => void) => void} removeHandler The function to remove a listener from the source.
 * @returns {AsyncIterableX<TSource>} An async-iterable which contains the data from the underlying events as wrapped by the handlers.
 */
export function fromEventPattern(addHandler, removeHandler, resultSelector) {
    if (!isFunction(resultSelector)) {
        resultSelector = identity;
    }
    var sink = new AsyncSink();
    var handler = function () {
        var args = [];
        for (var _i = 0; _i < arguments.length; _i++) {
            args[_i] = arguments[_i];
        }
        return sink.write(callOrApply(resultSelector, args));
    };
    addHandler(handler);
    var loop = function () {
        return __asyncGenerator(this, arguments, function () {
            var next;
            return __generator(this, function (_a) {
                switch (_a.label) {
                    case 0:
                        _a.trys.push([0, , 7, 8]);
                        next = void 0;
                        _a.label = 1;
                    case 1: return [4 /*yield*/, __await(sink.next())];
                    case 2:
                        if (!!(next = _a.sent()).done) return [3 /*break*/, 6];
                        return [4 /*yield*/, __await(next.value)];
                    case 3: return [4 /*yield*/, _a.sent()];
                    case 4:
                        _a.sent();
                        _a.label = 5;
                    case 5: return [3 /*break*/, 1];
                    case 6: return [3 /*break*/, 8];
                    case 7:
                        removeHandler(handler);
                        sink.end();
                        return [7 /*endfinally*/];
                    case 8: return [2 /*return*/];
                }
            });
        });
    };
    return memoize()(loop());
}

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