react/packages/shared/enqueueTask.js

49 lines
1.8 KiB
JavaScript

/**
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
* @flow
*/
let didWarnAboutMessageChannel = false;
let enqueueTaskImpl = null;
export default function enqueueTask(task: () => void) {
if (enqueueTaskImpl === null) {
try {
// read require off the module object to get around the bundlers.
// we don't want them to detect a require and bundle a Node polyfill.
const requireString = ('require' + Math.random()).slice(0, 7);
const nodeRequire = module && module[requireString];
// assuming we're in node, let's try to get node's
// version of setImmediate, bypassing fake timers if any.
enqueueTaskImpl = nodeRequire.call(module, 'timers').setImmediate;
} catch (_err) {
// we're in a browser
// we can't use regular timers because they may still be faked
// so we try MessageChannel+postMessage instead
enqueueTaskImpl = function(callback: () => void) {
if (__DEV__) {
if (didWarnAboutMessageChannel === false) {
didWarnAboutMessageChannel = true;
if (typeof MessageChannel === 'undefined') {
console.error(
'This browser does not have a MessageChannel implementation, ' +
'so enqueuing tasks via await act(async () => ...) will fail. ' +
'Please file an issue at https://github.com/facebook/react/issues ' +
'if you encounter this warning.',
);
}
}
}
const channel = new MessageChannel();
channel.port1.onmessage = callback;
channel.port2.postMessage(undefined);
};
}
}
return enqueueTaskImpl(task);
}