学习JavaScript设计模式之迭代器模式

$.each([1, 2, 3], function(i, n) {  console.log("当前下标为："+ i + " 当前元素为："+ n );});

var each = function(ary, callback) {  for(var i = 0, l = ary.length; i < l; i++) {    callback.call(ary[i], i, ary[i]);  }  };each([1, 2, 3], function(i, n) {  console.log("当前下标为："+ i + " 当前元素为："+ n );});

[1, 2, 3].forEach(function(n, i, curAry){  console.log("当前下标为："+ i + " 当前元素为："+ n + " 当前数组为：" + curAry);})

// 内部迭代器var each = function(ary, callback) {  for(var i = 0, l = ary.length; i < l; i++) {    callback.call(ary[i], i, ary[i]);  }  };// 比较函数var compareAry = function(ary1, ary2) {  if(ary1.length != ary2.length) {    throw new Error("不相等"); // return console.log("不相等");   }  // 且住  each(ary1, function(i, n) {    if(n !== ary2[i]) {      // return console.log("不相等");       // return 只能返回到each方法外，后续console.log("相等")会继续执行，所以这里得使用throw      throw new Error("不相等");    }  });  console.log("相等");}compareAry([1, 2, 3], [1, 2, 4]);

// 外部迭代器var Iterator = function(obj) {  var current = 0,    next = function() {      current++;    },    isDone = function() {      return current >= obj.length;      },    getCurrentItem = function() {      return obj[current];    };  return {    next: next,    isDone: isDone,    getCurrentItem: getCurrentItem  };};// 比较函数var compareAry = function(iterator1, iterator2) {  while( !iterator1.isDone() && !iterator2.isDone() ){    if(iterator1.getCurrentItem() !== iterator2.getCurrentItem()) {      throw new Error("不相等");    }    iterator1.next();    iterator2.next();  }  console.log("相等");}compareAry(new Iterator([1, 2, 3]), new Iterator([1, 2, 4]));

var each = function(ary, callback) {  for(var i = 0, l = ary.length; i < l; i++) {    if(callback.call(ary[i], i, ary[i]) === false) {      break;    }  }}each([1, 2, 4, 1], function(i, n) {  if(n > 3) {    return false;  }  console.log(n);});

var iteratorUploadObj = function() {  for(var i = 0, fn; fn = arguments[i]; i++) {    var uploadObj = fn();    if(uploadObj !== false) {      return uploadObj;    }  }};var uploadObj = iteratorUploadObj(getActiveUploadObj, getFlashUploadObj, getFormUploadObj);function getActiveUploadObj() {  try{    return new ActiveObject("TXFTNActiveX.FTNUpload"); // IE上传控件  }catch(e) {    return false;  }}function getFlashUploadObj() {  if(supportFlash().f === 1) {    var str = '<object type="application/x-shockwave-flash"></object>';    return $(str).appendTo($("body"));  }  return false;}function getFormUploadObj() {  var str = '<input name="file" type="file" class="ui-file" />';  return $(str).appendTo($("body"));}// 是否支持flashfunction supportFlash() {  var hasFlash = 0; //是否安装了flash  var flashVersion = 0; //flash版本  if (document.all) {    var swf = new ActiveXObject('ShockwaveFlash.ShockwaveFlash');    if (swf) {      hasFlash = 1;      VSwf = swf.GetVariable("$version");      flashVersion = parseInt(VSwf.split(" ")[1].split(",")[0]);    }  } else {    if (navigator.plugins && navigator.plugins.length > 0) {    var swf = navigator.plugins["Shockwave Flash"];      if (swf) {        hasFlash = 1;        var words = swf.description.split(" ");        for (var i = 0; i < words.length; ++i) {          if (isNaN(parseInt(words[i]))) continue;          flashVersion = parseInt(words[i]);        }      }    }  }  return { f: hasFlash, v: flashVersion };}