You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 

81 lines
2.8 KiB

'use strict';
var global = require('../internals/global');
var bind = require('../internals/function-bind-context');
var getOwnPropertyDescriptor = require('../internals/object-get-own-property-descriptor').f;
var macrotask = require('../internals/task').set;
var Queue = require('../internals/queue');
var IS_IOS = require('../internals/engine-is-ios');
var IS_IOS_PEBBLE = require('../internals/engine-is-ios-pebble');
var IS_WEBOS_WEBKIT = require('../internals/engine-is-webos-webkit');
var IS_NODE = require('../internals/engine-is-node');
var MutationObserver = global.MutationObserver || global.WebKitMutationObserver;
var document = global.document;
var process = global.process;
var Promise = global.Promise;
// Node.js 11 shows ExperimentalWarning on getting `queueMicrotask`
var queueMicrotaskDescriptor = getOwnPropertyDescriptor(global, 'queueMicrotask');
var microtask = queueMicrotaskDescriptor && queueMicrotaskDescriptor.value;
var notify, toggle, node, promise, then;
// modern engines have queueMicrotask method
if (!microtask) {
var queue = new Queue();
var flush = function () {
var parent, fn;
if (IS_NODE && (parent = process.domain)) parent.exit();
while (fn = queue.get()) try {
fn();
} catch (error) {
if (queue.head) notify();
throw error;
}
if (parent) parent.enter();
};
// browsers with MutationObserver, except iOS - https://github.com/zloirock/core-js/issues/339
// also except WebOS Webkit https://github.com/zloirock/core-js/issues/898
if (!IS_IOS && !IS_NODE && !IS_WEBOS_WEBKIT && MutationObserver && document) {
toggle = true;
node = document.createTextNode('');
new MutationObserver(flush).observe(node, { characterData: true });
notify = function () {
node.data = toggle = !toggle;
};
// environments with maybe non-completely correct, but existent Promise
} else if (!IS_IOS_PEBBLE && Promise && Promise.resolve) {
// Promise.resolve without an argument throws an error in LG WebOS 2
promise = Promise.resolve(undefined);
// workaround of WebKit ~ iOS Safari 10.1 bug
promise.constructor = Promise;
then = bind(promise.then, promise);
notify = function () {
then(flush);
};
// Node.js without promises
} else if (IS_NODE) {
notify = function () {
process.nextTick(flush);
};
// for other environments - macrotask based on:
// - setImmediate
// - MessageChannel
// - window.postMessage
// - onreadystatechange
// - setTimeout
} else {
// `webpack` dev server bug on IE global methods - use bind(fn, global)
macrotask = bind(macrotask, global);
notify = function () {
macrotask(flush);
};
}
microtask = function (fn) {
if (!queue.head) notify();
queue.add(fn);
};
}
module.exports = microtask;