草庐IT

javascript - react : TypeError: Cannot read property 'propTypes' of undefined

请我为以下reactjs页面编写一个单元测试。exportdefaultclassCollapsibleextendsReact.Component{staticpropTypes={title:React.PropTypes.string,children:React.PropTypes.any,};render(){const{title}=this.props;return({title}{this.props.children});}}跟着啧啧Here我在下面写了我的测试describe('Collapsible',()=>{it('works',()=>{letrendere

javascript - [Vue 警告] : Error in render function: "TypeError: Cannot read property ' first_name' of null"

我有以下Navigation.vue组件:{{user.first_name}}import{mapActions,mapGetters}from'vuex'exportdefault{name:'hello',methods:{...mapActions(['myAccount'])},mounted:function(){if(localStorage.getItem('access_token')){this.myAccount()}},computed:{...mapGetters(['user'])}}此代码返回:[Vuewarn]:Errorinrenderfunction

javascript - 未捕获的类型错误 : Cannot read property 'offsetWidth' of null

这个问题在这里已经有了答案:GoogleMAPAPIUncaughtTypeError:Cannotreadproperty'offsetWidth'ofnull(26个答案)OffsetWidthnullorundefined(Can'tfindsolution)[closed](1个回答)关闭8年前。不幸的是,我在发布这个问题之前阅读了几个线程,我找不到适合我的问题的答案。这是我的代码片段-->functionpopulateIframe(id){varifrm=document.getElementById(id);ifrm.src="business_data_to_excel

javascript - Angular2 - 类型错误 : Cannot read property 'Id' of undefined in (Typescript)

我收到以下错误:angular2.dev.js:23925EXCEPTION:TypeError:Cannotreadproperty'Id'ofnullin[{{product.Id}}inProductEditComponent@0:68]抛出://Product-edit.component.ts:import{Component}from'angular2/core';import{IProduct}from'./product'import{ProductService}from'./product.service'import{RouteParams}from'angula

javascript - Gulp with browserify : Cannot find module src/js/main. js

我正在尝试使用Gulp和browserify进行基本build设置,但在尝试运行默认任务时不断看到此错误:Error:Cannotfindmodule'src/js/main.js'from'/Users/ben/dev/git/myapp/'gulp文件.jsvargulp=require('gulp');varbrowserify=require('browserify');vardel=require('del');varsource=require('vinyl-source-stream');varpaths={main_js:['src/js/main.js'],js:['

javascript - react - 类型错误 : Cannot read property 'props' of undefined

我正在尝试创建一个能够删除列表中项目的点击事件,但是当我点击它时,我得到“类型错误:无法读取未定义的属性‘props’”。我尽量坚持使用ES6,而且我很确定在某处绑定(bind)“this”是一件好事,但我尝试了很多地方但都没有成功。importReact,{Component}from'react';import'./App.css';classAppextendsComponent{render(){return();}}classStreetFighterextendsComponent{constructor(props){super(props);this.state={ch

javascript - GraphQL 查询返回错误 "Cannot return null for non-nullable field"

我有一个基本的GraphQL查询设置,如下所示:查询.js:constQuery={dogs(parent,args,ctx,info){return[{name:'Snickers'},{name:'Sunny'}];},};module.exports=Query;schema.graphql:typeDog{name:String!}typeQuery{dogs:[Dog]!}我创建了一个函数createServer()来启动服务器,如下所示:const{GraphQLServer}=require('graphql-yoga');constMutation=require('.

javascript - 导入 anuglar2/forms 导致 "Cannot read property ' 未定义注释”

我正在尝试创建简单的表单,如http://angularjs.blogspot.no/2015/03/forms-in-angular-2.html中所述,但是当我添加从'angular2/forms'导入{forms,required};在崩溃中TypeError:Cannotreadproperty'annotations'ofundefinedTypeError:Cannotreadproperty'annotations'ofundefinedatReflectionCapabilities.System.register.execute.$__export.annotatio

javascript - 编译器不抛出 "Cannot find module"错误

在我的项目中我有2个文件:foo.jsconstimage=require('../this/path/is/wrong.png');boo.tsxconstimage=require('../this/path/is/wrong.png');在foo.js中TypeScript正确的发现图片不存在并抛出“Cannotfindmodule”错误,但是对于boo.tsx没有抛出错误所以该错误仅在应用程序崩溃时出现在运行时。如果我只是将boo.tsx重命名为boo.jsTS再次开始按预期抛出错误。这些是我认为可能相关的一些编译器选项:"module":"es2015","target":"

javascript - promise - TypeError : Cannot read property 'then' of undefined

我想我只需要另一双眼睛看这个,因为我无法得到我在这里缺少的东西。$scope.checkout=function(form){//somecodeherefunctioncheckoutErrorHandler(error){//somecodehere}functiondisplaySuccessMessage(){$scope.success=true;cartService.emptyCart();}checkoutService.makePayment($scope.payment).then(function(i){//somecodeherecheckoutService.