schedule.js

"use strict";
var schedule;
var util = require("./util");
var noAsyncScheduler = function() {
    throw new Error("No async scheduler available\u000a\u000a    See http://goo.gl/m3OTXk\u000a");
};
if (util.isNode && typeof MutationObserver === "undefined") {
    var GlobalSetImmediate = global.setImmediate;
    var ProcessNextTick = process.nextTick;
    schedule = util.isRecentNode
                ? function(fn) { GlobalSetImmediate.call(global, fn); }
                : function(fn) { ProcessNextTick.call(process, fn); };
} else if (typeof MutationObserver !== "undefined") {
    schedule = function(fn) {
        var div = document.createElement("div");
        var observer = new MutationObserver(fn);
        observer.observe(div, {attributes: true});
        return function() { div.classList.toggle("foo"); };
    };
    schedule.isStatic = true;
} else if (typeof setImmediate !== "undefined") {
    schedule = function (fn) {
        setImmediate(fn);
    };
} else if (typeof setTimeout !== "undefined") {
    schedule = function (fn) {
        setTimeout(fn, 0);
    };
} else {
    schedule = noAsyncScheduler;
}
module.exports = schedule;