cwait/dist/esm/Task.js

Limit number of promises running in parallel

// This file is part of cwait, copyright (c) 2015- BusFaster Ltd.
// Released under the MIT license, see LICENSE.
/** Call func and return a promise for its result.
  * Optionally call given resolve or reject handler when the promise settles. */
export function tryFinally(func, onFinish, Promise, resolve, reject) {
    var promise;
    try {
        promise = Promise.resolve(func());
    }
    catch (err) {
        // If func threw an error, return a rejected promise.
        promise = Promise.reject(err);
    }
    promise.then(onFinish, onFinish);
    if (resolve)
        promise.then(resolve, reject);
    return (promise);
}
/** Task wraps a promise, delaying it until some resource gets less busy. */
var Task = /** @class */ (function () {
    function Task(func, Promise, stamp) {
        this.func = func;
        this.Promise = Promise;
        this.stamp = stamp;
    }
    /** Wrap task result in a new promise so it can be resolved later. */
    Task.prototype.delay = function () {
        var _this = this;
        if (!this.promise) {
            this.promise = new this.Promise(function (resolve, reject) {
                _this.resolve = resolve;
                _this.reject = reject;
            });
        }
        return (this.promise);
    };
    /** Start the task and call onFinish when done. */
    Task.prototype.resume = function (onFinish) {
        return (tryFinally(this.func, onFinish, this.Promise, this.resolve, this.reject));
    };
    return Task;
}());
export { Task };