Current Dev State

static/js/ketcher2/node_modules/when/poll.js

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+/** @license MIT License (c) copyright 2012-2013 original author or authors */
+
+/**
+ * poll.js
+ *
+ * Helper that polls until cancelled or for a condition to become true.
+ *
+ * @author Scott Andrews
+ */
+
+(function (define) { 'use strict';
+define(function(require) {
+
+	var when = require('./when');
+	var attempt = when['try'];
+	var cancelable = require('./cancelable');
+
+	/**
+	 * Periodically execute the task function on the msec delay. The result of
+	 * the task may be verified by watching for a condition to become true. The
+	 * returned deferred is cancellable if the polling needs to be cancelled
+	 * externally before reaching a resolved state.
+	 *
+	 * The next vote is scheduled after the results of the current vote are
+	 * verified and rejected.
+	 *
+	 * Polling may be terminated by the verifier returning a truthy value,
+	 * invoking cancel() on the returned promise, or the task function returning
+	 * a rejected promise.
+	 *
+	 * Usage:
+	 *
+	 * var count = 0;
+	 * function doSomething() { return count++ }
+	 *
+	 * // poll until cancelled
+	 * var p = poll(doSomething, 1000);
+	 * ...
+	 * p.cancel();
+	 *
+	 * // poll until condition is met
+	 * poll(doSomething, 1000, function(result) { return result > 10 })
+	 *     .then(function(result) { assert result == 10 });
+	 *
+	 * // delay first vote
+	 * poll(doSomething, 1000, anyFunc, true);
+	 *
+	 * @param task {Function} function that is executed after every timeout
+	 * @param interval {number|Function} timeout in milliseconds
+	 * @param [verifier] {Function} function to evaluate the result of the vote.
+	 *     May return a {Promise} or a {Boolean}. Rejecting the promise or a
+	 *     falsey value will schedule the next vote.
+	 * @param [delayInitialTask] {boolean} if truthy, the first vote is scheduled
+	 *     instead of immediate
+	 *
+	 * @returns {Promise}
+	 */
+	return function poll(task, interval, verifier, delayInitialTask) {
+		var deferred, canceled, reject;
+
+		canceled = false;
+		deferred = cancelable(when.defer(), function () { canceled = true; });
+		reject = deferred.reject;
+
+		verifier = verifier || function () { return false; };
+
+		if (typeof interval !== 'function') {
+			interval = (function (interval) {
+				return function () { return when().delay(interval); };
+			})(interval);
+		}
+
+		function certify(result) {
+			deferred.resolve(result);
+		}
+
+		function schedule(result) {
+			attempt(interval).then(vote, reject);
+			if (result !== void 0) {
+				deferred.notify(result);
+			}
+		}
+
+		function vote() {
+			if (canceled) { return; }
+			when(task(),
+				function (result) {
+					when(verifier(result),
+						function (verification) {
+							return verification ? certify(result) : schedule(result);
+						},
+						function () { schedule(result); }
+					);
+				},
+				reject
+			);
+		}
+
+		if (delayInitialTask) {
+			schedule();
+		} else {
+			// if task() is blocking, vote will also block
+			vote();
+		}
+
+		// make the promise cancelable
+		deferred.promise = Object.create(deferred.promise);
+		deferred.promise.cancel = deferred.cancel;
+
+		return deferred.promise;
+	};
+
+});
+})(typeof define === 'function' && define.amd ? define : function (factory) { module.exports = factory(require); });