Javascript Error : While using array destructuring

Question

  var [a,b] = list
  console.log("a ",a)    // a = 1
  console.log("b ",b)    // b = 2

  [a,b] = [b,a]

  console.log("a ",a)    // a = 2
  console.log("b ",b)    // b = 1

VM247:3 个 1 VM247:4 b 2 VM247:6 未捕获类型错误：无法设置未定义的属性 '2' 在 :6:9

Answer 1

由于编译受到影响，您的代码中缺少分号

console.log("b ",b)    // b = 2

[a,b] = [b,a]

被视为

console.log("b ",b)[a,b] = [b,a]    // b = 2

即它尝试从未定义的 console.log return 值访问密钥

工作演示

var list=["Hello", "World"];
var [a,b] = list;
  console.log("a ",a);    // a = 1
  console.log("b ",b);    // b = 2

  [a,b] = [b,a];

  console.log("a ",a)    // a = 2
  console.log("b ",b)    // b = 1

Javascript Error : While using array destructuring

Javascript Error : While using array destructuring

javascript

arrays

destructuring