嵌套的辅助函数可以使您的代码更易于理解.谷歌甚至建议在他们的style guide中使用嵌套函数.我想知道这些嵌套函数和性能的实例化.例如,work(1); work(2);function work(a) {// do some stufflog();// do some more stufffunction log() {console.log(a);} }工作实例化一次,但是日志实例化两次？ 如果每次执行工作时都会实例化log,那么通常建议不要嵌套函数吗？相反,编写如下代码work(1); work(2);function work(a) {// do some stuf...
如何遍历嵌套的firebase对象.Publications-||-Folder1------| |-hdgjg76675e6r-| | |-Name| | |-Author| || |+-hdgjdsf3275e6k| |+-hd345454575e6f|+-Folder2在出版物我有文件夹和文件夹我有对象(包含属性,如.姓名,作者) 我已经遍历文件夹到现在为止.snapshot.forEach(function (snapshot) {var key = snapshot.key();var o...
我用React应用程序打了一个兔子洞.我循环遍历这个对象数组：const weeklyClasses = [{id: 1,day: "Monday",classDescription: [{ classType: "11am-12pm Jazz", teacher: "Joe" },{ classType: "1pm-2pm Blues", teacher: "Doe" },{ classType: "3pm-4pm Samba", teacher: "Zen" }]},{id: 1,day: "Tuesday",classDescription: [{ classType: "11am-12pm Rock", teacher: "Sis" },{ classType: "1pm-2pm Tango", teacher: "Ter" },{...
我正在用javascript编写一个记忆游戏.我为这些卡制作了一个网络组件,< memory-card>以及包含卡片并处理游戏状态< memory-game>的网络组件. <存储卡> class包含其翻转时的图像路径,默认图像显示为卡的背面,其转动状态和onclick功能,以处理状态和图像之间的切换. <记忆游戏> class有一个setter,它接收一组图像以生成< memory-cards>从.在< memory-game>中处理更新游戏状态的最佳方法是什么？类？我应该将附加事件监听器附加到< memor...
我有一系列的钥匙：var keys = ['key1', 'key2', 'key3'];如何以最简单的方式创建此类对象？var object = { 'key1' : { 'key2' : {'key3' : 'value' }}}解决方法:您可以利用JavaScript存储对象的引用这一事实：var keys = ['key1', 'key2', 'key3']; // input data var object = {}; // output data var current = object; // we will use this to recursively insert// a new objectfor(var i...
我使用cycle2插件显示由一些图像和另一个幻灯片组成的幻灯片.内部幻灯片的下一个和上一个按钮由于某些原因(在示例中向上和向下)不起作用,尽管它们已正确设置恕我直言：data-cycle-prev="#upDiv" data-cycle-next="#downDiv"和<div id="upDiv"><a href="#" id="upImg"><img src="images/up.png" alt="" /></a><p>scroll up</p> </div> <div id="downDiv"><p>to see more scroll down</p><a href="#" id="downImg"><img src="images/...
我有一个具有未知数量的级别和类型(数组,对象,字符串)的对象,这是一个示例：var data = {ffs: false,customer: {customer_id: 1544248,z_cx_id: '123456',},selected_items: {'3600196': [{id: 4122652,name: 'Essential Large (up to 8\'x10\')',selected: true}]},service_partner: {id: 3486,name: 'Some String',street: '1234 King St.',},subject: 'Project-2810191 - Orange Juice Stain (Rug)',description: 'Product Type...
我试图使用Vue.set()来更新Vue 2中的状态对象. 这是对象的样子：state: {entries: [// entry 1fields: {someProperties : ''// here I would like to add another property named 'googleInfos'}], [// entry 2fields: {someProperties : ''// here I would like to add another property named 'googleInfos'}] }到目前为止,我正在用这个突变更新它.我正在分别改变每个条目,因为它们有不同的内容.ADD_GOOGLE_INFOS (state, {index...
我原以为单/双引号在Javascript中是可以互换的.所以在jQuery函数中,任何人都可以解释原因：$('input:radio[name='+foo+'][value='+bar+']').attr('checked', true);有效,但是$('input:radio[name="+foo+"][value="+bar+"]').attr('checked', true);不？ (如果foo和bar都是字符串.) 单引号双单引号双引号不起作用吗？解决方法:如果在另一个引用中使用一种引用类型,在大多数现代JavaScript引擎中,它会将内部,交替类型引号视为引号字符...
我用xml试过这个,但是从firefox到IE的行为很奇怪.我之前没有和json合作过,所以任何帮助都会受到赞赏. 这是我的json：{"storeList":{"state":[{"stateName":"Maine","store":[{"storeName":"Store 1","storeID":"store1","storeURL":"http:\/\/www.sitename.com"},{"storeName":"Store 2","storeID":"store2","storeURL":"http:\/\/www.sitename.com"},{"storeName":"Store 3","storeID":"store3","storeURL":"http:\/\/www.sitenam...
参见英文答案 > Javascript: how to dynamically create nested objects using object names given by an array 17个我有以下对象：var object = {"property1": "value1","property2": "value2","subobject": {"property1": "value1","property2": "value2","subobject": {"property1": "value1","property2": "value2","subobject": {...}}} }我试图设置一个嵌套的子对象属性,但嵌套级别是动态...
我有两个json对象工作[ { "code":"Maxo- 1033","title":"Test","deleted_by":2,"updated_at":"2017-08-23 06:32:42"},{ "code":"Maxo- 1034","title":"Test","deleted_by":2,"updated_at":"2017-08-24 04:55:10"} ]其他是标题[ "code","title","deleted_by","updated_at" ]我想使用标题数据打印作业数据像下面的代码.<tbody><tr ng-repeat = 'job in jobs'><td ng-repeat = 'column in headers'> @{{job.column}} //i want jo...
js避免深层嵌套let ok = function () {}let no = function () {}let error = function () {}let hashMap = {'200': ok,'404': no,'500': error}let status = res.status // 异步获取状态码if(status in hashMap) {hashMap[status]();}$.ajax().done(function (res) {switch (res.state) {case 'SUCCESS'://TODObreak;case 'FAIL'://TODObreak;default ://TODO} });
新手问题：我有一个包含大量字符串的“开关”.按字母顺序分割是否有速度优势,就像这样？switch(myString.substring(0,1)){ case "a" : switch(myString){case "a string beginning with a" : runCode(); break;case "another string beginning with a" : runCode(); break;} break; case "b" : switch(myString){case "by golly another string" : runCode(); break;case "blimey - hundreds of strings" : runCo...
我正在尝试在Codecademy中学习JavaScript,其中一个简单的提到是“for in”循环.我在一些练习中使用过它们,但在这种情况下,我无法让它工作.我可以用(i =等等;等等),但我想知道这有什么问题,如果有办法解决它：//Your three dimensional array from the last exercise probably //looked something like this: var hands = []; hands[0] = [ [3,"H"], ["A","S"], [1,"D"], ["J","H"], ["Q","D"] ]; hands[1] = [ [9,"C"], [6,"C"], [...