Even if you try to change the object structure, the compiler will point this error out. constplayerCodes={player1:9,player2:10,player3:13,player4:20};playerCodes={//Compiler Error: Cannot assign to playerCodes because it is a constant or read-onlyplayer1:9,player2:10,player3:13,player4:20,player5:22}; Watch more videos
// 中查询对应的store,保证不同组件使用相同的store const state = scope.runstring, StateTree>>>(() =>...构建useState函数 这里主要看useState做了什么 // 通过配置类型判断配置类型 const isSetupStore = typeof setup === 'function' ..._s.has(id)) { // 如果未在...
Variables declared byvarandconstkeywords arefunction scopedand are scoped to the immediate function body. Also, variables declared withvarkeyword are hoisted (initialized withundefinedbefore the code is run) which means they are accessible in their enclosing scope even before they are declared. Variable...
基于安全考虑,Gitee 建议 配置并使用私人令牌 替代登录密码进行克隆、推送等操作 Username for 'https://gitee.com': userName Password for 'https://userName@gitee.com': # 私人令牌 main 分支(1) 管理 管理 main chatbot-ui-lite / package-lock.json package-lock.json 255.16 KB ...
四个方面对比var、let、const声明的变量差异 var 在ES6 之前我们都是通过var关键字定义 JavaScript 变量。ES6 才新增了let和const关键字 var num = 1 在全局作用域下使用var声明一个变量,默认它是挂载在顶层对象window对象下(Node 是global) var num = 1 ...
Use theletstatement to declare a variable, when thescope MUST BE restricted to the block in which it is declared. functionfun() { letdataX = 10; if(true) { letdataY = 20; console.log(dataX);//Output 10 console.log(dataY);//Output 20 ...