25. Iterator pattern

var Iterator = function(items, container) { var container = contaner || document.getElementById(container) || document var items = container.getElementByTagName(items) var length = items.length, index = 0 var splice = [].splice return { first: function() { index = 0 return items.index[0] }, next: function() { if(++index < length) { return item[index] } else { index = length -1 return null } }, get: function(num) { index = num > 0 ? num % length : num % length +length; return items[index] }, dealEach: function(fun) { var args = Array.prototype.slice(arguments, 1) for (let index = 0; index < length; index++) { fun.apply(item[i], args) } }, dealItem: function(num, fun) { fun.apply(this.get(num), Array.prototype.slice(arguments, 2)) }, exclusive: function(num, allFun, numFun) { this.dealEach(allFun) if(Object.prototype.toString.call(num) === '[object Array]') { for(var i = 0, len = num.length; i < len; i++) { this.dealItem(num[i], numFun) } } else { this.dealItem(num, numFun) } }, Var ArrayIterator = function(arr, fun) {for(var I = 0; i< arr.length; i++) { if(fun.call(arr[i], i, arr[i]) === false) { break; } // fun.apply(i,arr[i]) } } var eachObject = function(obj, fun) { for(var i in obj) { if(fun.call(obj[i], i , obj[i]) === false) { break; } } } var A = { client: { user: { name: 'guohua' } } } function Agetter(key) { if(! A) return undefined var result = A var key = key.split('.') for (let index = 0; index < key.length; index++) { const element = key[index]; if(result[element] ! == 'undefined') { result = result[element] } else { return undefined } } return result } console.log(Agetter('client.user.name'))Copy the code