首页 > 代码库 > [ES6] 04. The let keyword -- 2 Fiald case
[ES6] 04. The let keyword -- 2 Fiald case
Fiald case 1: let can work in it‘s block
{ let a = 10; var b = 1;}a // ReferenceError: a is not defined.b //1
Case 2: Let has no "Hosting" Problem
function do_something() { console.log(foo); // ReferenceError let foo = 2;}
function do_something() { console.log(foo); //undefined var foo = 2;}//hosting:function do_something() { var foo = undefined; console.log(foo); foo = 2;}
Case 3: let不允许在相同作用域内，重复声明同一个变量: In a block, you can only define one variable one time.
// 报错{ let a = 10; var a = 1;}// 报错{ let a = 10; let a = 1;}
But if you do something like:
function f1() { let n = 5; if (true) { let n = 10; } console.log(n); // 5}
There is no problem! becuase 5 and 10 are in different block scope.
[ES6] 04. The let keyword -- 2 Fiald case
声明：以上内容来自用户投稿及互联网公开渠道收集整理发布，本网站不拥有所有权，未作人工编辑处理，也不承担相关法律责任，若内容有误或涉及侵权可进行投诉： 投诉/举报 工作人员会在5个工作日内联系你，一经查实，本站将立刻删除涉嫌侵权内容。