wishthis/node_modules/next-tick/index.js
2022-03-14 16:40:45 +01:00

74 lines
2 KiB
JavaScript

'use strict';
var ensureCallable = function (fn) {
if (typeof fn !== 'function') throw new TypeError(fn + " is not a function");
return fn;
};
var byObserver = function (Observer) {
var node = document.createTextNode(''), queue, currentQueue, i = 0;
new Observer(function () {
var callback;
if (!queue) {
if (!currentQueue) return;
queue = currentQueue;
} else if (currentQueue) {
queue = currentQueue.concat(queue);
}
currentQueue = queue;
queue = null;
if (typeof currentQueue === 'function') {
callback = currentQueue;
currentQueue = null;
callback();
return;
}
node.data = (i = ++i % 2); // Invoke other batch, to handle leftover callbacks in case of crash
while (currentQueue) {
callback = currentQueue.shift();
if (!currentQueue.length) currentQueue = null;
callback();
}
}).observe(node, { characterData: true });
return function (fn) {
ensureCallable(fn);
if (queue) {
if (typeof queue === 'function') queue = [queue, fn];
else queue.push(fn);
return;
}
queue = fn;
node.data = (i = ++i % 2);
};
};
module.exports = (function () {
// Node.js
if ((typeof process === 'object') && process && (typeof process.nextTick === 'function')) {
return process.nextTick;
}
// queueMicrotask
if (typeof queueMicrotask === "function") {
return function (cb) { queueMicrotask(ensureCallable(cb)); };
}
// MutationObserver
if ((typeof document === 'object') && document) {
if (typeof MutationObserver === 'function') return byObserver(MutationObserver);
if (typeof WebKitMutationObserver === 'function') return byObserver(WebKitMutationObserver);
}
// W3C Draft
// http://dvcs.w3.org/hg/webperf/raw-file/tip/specs/setImmediate/Overview.html
if (typeof setImmediate === 'function') {
return function (cb) { setImmediate(ensureCallable(cb)); };
}
// Wide available standard
if ((typeof setTimeout === 'function') || (typeof setTimeout === 'object')) {
return function (cb) { setTimeout(ensureCallable(cb), 0); };
}
return null;
}());