TrinetraLabs/Placebo_AI

1'use strict';2var Mutation = global.MutationObserver || global.WebKitMutationObserver;3 4var scheduleDrain;5 6if (process.browser) {7  if (Mutation) {8    var called = 0;9    var observer = new Mutation(nextTick);10    var element = global.document.createTextNode('');11    observer.observe(element, {12      characterData: true13    });14    scheduleDrain = function () {15      element.data = (called = ++called % 2);16    };17  } else if (!global.setImmediate && typeof global.MessageChannel !== 'undefined') {18    var channel = new global.MessageChannel();19    channel.port1.onmessage = nextTick;20    scheduleDrain = function () {21      channel.port2.postMessage(0);22    };23  } else if ('document' in global && 'onreadystatechange' in global.document.createElement('script')) {24    scheduleDrain = function () {25 26      // Create a <script> element; its readystatechange event will be fired asynchronously once it is inserted27      // into the document. Do so, thus queuing up the task. Remember to clean up once it's been called.28      var scriptEl = global.document.createElement('script');29      scriptEl.onreadystatechange = function () {30        nextTick();31 32        scriptEl.onreadystatechange = null;33        scriptEl.parentNode.removeChild(scriptEl);34        scriptEl = null;35      };36      global.document.documentElement.appendChild(scriptEl);37    };38  } else {39    scheduleDrain = function () {40      setTimeout(nextTick, 0);41    };42  }43} else {44  scheduleDrain = function () {45    process.nextTick(nextTick);46  };47}48 49var draining;50var queue = [];51//named nextTick for less confusing stack traces52function nextTick() {53  draining = true;54  var i, oldQueue;55  var len = queue.length;56  while (len) {57    oldQueue = queue;58    queue = [];59    i = -1;60    while (++i < len) {61      oldQueue[i]();62    }63    len = queue.length;64  }65  draining = false;66}67 68module.exports = immediate;69function immediate(task) {70  if (queue.push(task) === 1 && !draining) {71    scheduleDrain();72  }73}74