79 lines
2.4 KiB
JavaScript
79 lines
2.4 KiB
JavaScript
var global = require('../internals/global');
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var getOwnPropertyDescriptor = require('../internals/object-get-own-property-descriptor').f;
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var classof = require('../internals/classof-raw');
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var macrotask = require('../internals/task').set;
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var IS_IOS = require('../internals/engine-is-ios');
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var MutationObserver = global.MutationObserver || global.WebKitMutationObserver;
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var process = global.process;
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var Promise = global.Promise;
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var IS_NODE = classof(process) == 'process';
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// Node.js 11 shows ExperimentalWarning on getting `queueMicrotask`
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var queueMicrotaskDescriptor = getOwnPropertyDescriptor(global, 'queueMicrotask');
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var queueMicrotask = queueMicrotaskDescriptor && queueMicrotaskDescriptor.value;
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var flush, head, last, notify, toggle, node, promise, then;
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// modern engines have queueMicrotask method
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if (!queueMicrotask) {
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flush = function () {
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var parent, fn;
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if (IS_NODE && (parent = process.domain)) parent.exit();
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while (head) {
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fn = head.fn;
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head = head.next;
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try {
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fn();
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} catch (error) {
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if (head) notify();
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else last = undefined;
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throw error;
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}
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} last = undefined;
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if (parent) parent.enter();
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};
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// Node.js
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if (IS_NODE) {
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notify = function () {
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process.nextTick(flush);
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};
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// browsers with MutationObserver, except iOS - https://github.com/zloirock/core-js/issues/339
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} else if (MutationObserver && !IS_IOS) {
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toggle = true;
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node = document.createTextNode('');
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new MutationObserver(flush).observe(node, { characterData: true });
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notify = function () {
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node.data = toggle = !toggle;
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};
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// environments with maybe non-completely correct, but existent Promise
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} else if (Promise && Promise.resolve) {
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// Promise.resolve without an argument throws an error in LG WebOS 2
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promise = Promise.resolve(undefined);
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then = promise.then;
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notify = function () {
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then.call(promise, flush);
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};
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// for other environments - macrotask based on:
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// - setImmediate
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// - MessageChannel
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// - window.postMessag
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// - onreadystatechange
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// - setTimeout
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} else {
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notify = function () {
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// strange IE + webpack dev server bug - use .call(global)
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macrotask.call(global, flush);
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};
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}
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}
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module.exports = queueMicrotask || function (fn) {
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var task = { fn: fn, next: undefined };
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if (last) last.next = task;
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if (!head) {
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head = task;
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notify();
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} last = task;
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};
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