unhandledRejection.js

/** @license MIT License (c) copyright 2010-2014 original author or authors */
/** @author Brian Cavalier */
/** @author John Hann */

(function(define) { 'use strict';
define(function(require) {

	var setTimer = require('../env').setTimer;

	return function unhandledRejection(Promise) {
		var logError = noop;
		var logInfo = noop;

		if(typeof console !== 'undefined') {
			logError = typeof console.error !== 'undefined'
				? function (e) { console.error(e); }
				: function (e) { console.log(e); };

			logInfo = typeof console.info !== 'undefined'
				? function (e) { console.info(e); }
				: function (e) { console.log(e); };
		}

		Promise.onPotentiallyUnhandledRejection = function(rejection) {
			enqueue(report, rejection);
		};

		Promise.onPotentiallyUnhandledRejectionHandled = function(rejection) {
			enqueue(unreport, rejection);
		};

		Promise.onFatalRejection = function(rejection) {
			enqueue(throwit, rejection.value);
		};

		var tasks = [];
		var reported = [];
		var running = false;

		function report(r) {
			if(!r.handled) {
				reported.push(r);
				logError('Potentially unhandled rejection [' + r.id + '] ' + formatError(r.value));
			}
		}

		function unreport(r) {
			var i = reported.indexOf(r);
			if(i >= 0) {
				reported.splice(i, 1);
				logInfo('Handled previous rejection [' + r.id + '] ' + formatObject(r.value));
			}
		}

		function enqueue(f, x) {
			tasks.push(f, x);
			if(!running) {
				running = true;
				running = setTimer(flush, 0);
			}
		}

		function flush() {
			running = false;
			while(tasks.length > 0) {
				tasks.shift()(tasks.shift());
			}
		}

		return Promise;
	};

	function formatError(e) {
		var s = typeof e === 'object' && e.stack ? e.stack : formatObject(e);
		return e instanceof Error ? s : s + ' (WARNING: non-Error used)';
	}

	function formatObject(o) {
		var s = String(o);
		if(s === '[object Object]' && typeof JSON !== 'undefined') {
			s = tryStringify(o, s);
		}
		return s;
	}

	function tryStringify(e, defaultValue) {
		try {
			return JSON.stringify(e);
		} catch(e) {
			// Ignore. Cannot JSON.stringify e, stick with String(e)
			return defaultValue;
		}
	}

	function throwit(e) {
		throw e;
	}

	function noop() {}

});
}(typeof define === 'function' && define.amd ? define : function(factory) { module.exports = factory(require); }));