| var global = require('./_global') |
| , macrotask = require('./_task').set |
| , Observer = global.MutationObserver || global.WebKitMutationObserver |
| , process = global.process |
| , Promise = global.Promise |
| , isNode = require('./_cof')(process) == 'process'; |
| |
| module.exports = function(){ |
| var head, last, notify; |
| |
| var flush = function(){ |
| var parent, fn; |
| if(isNode && (parent = process.domain))parent.exit(); |
| while(head){ |
| fn = head.fn; |
| head = head.next; |
| try { |
| fn(); |
| } catch(e){ |
| if(head)notify(); |
| else last = undefined; |
| throw e; |
| } |
| } last = undefined; |
| if(parent)parent.enter(); |
| }; |
| |
| // Node.js |
| if(isNode){ |
| notify = function(){ |
| process.nextTick(flush); |
| }; |
| // browsers with MutationObserver |
| } else if(Observer){ |
| var toggle = true |
| , node = document.createTextNode(''); |
| new Observer(flush).observe(node, {characterData: true}); // eslint-disable-line no-new |
| notify = function(){ |
| node.data = toggle = !toggle; |
| }; |
| // environments with maybe non-completely correct, but existent Promise |
| } else if(Promise && Promise.resolve){ |
| var promise = Promise.resolve(); |
| notify = function(){ |
| promise.then(flush); |
| }; |
| // for other environments - macrotask based on: |
| // - setImmediate |
| // - MessageChannel |
| // - window.postMessag |
| // - onreadystatechange |
| // - setTimeout |
| } else { |
| notify = function(){ |
| // strange IE + webpack dev server bug - use .call(global) |
| macrotask.call(global, flush); |
| }; |
| } |
| |
| return function(fn){ |
| var task = {fn: fn, next: undefined}; |
| if(last)last.next = task; |
| if(!head){ |
| head = task; |
| notify(); |
| } last = task; |
| }; |
| }; |