基于ES6作用域和解构赋值详解

// const声明的k指向一个对象，k本身不可变，但对象可变function test() { const k={  a:1 } k.b=3;  console.log(k);}

{ let a, b, 3, rest; [a, b, c=3]=[1, 2]; console.log(a, b);}//output: 1 2 3{ let a, b, 3, rest; [a, b, c]=[1, 2]; console.log(a, b);}//output: 1 2 undefined{ let a, b, rest; [a, b, ...rest] = [1, 2, 3, 4, 5, 6]; console.log(a, b, rest);}//output:1 2 [3, 4, 5, 6]{ let a, b; ({a, b} = {a:1, b:2}) console.log(a ,b);}//output: 1 2

{ let a = 1; let b = 2; [a, b] = [b, a]; console.log(a, b);}

{ function f(){  return [1, 2] } let a, b; [a, b] = f(); console.log(a, b);}

{ function f(){  return [1, 2, 3, 4, 5] } let a, b, c; [a,,,b] = f(); console.log(a, b);}//output: 1 4{ function f(){  return [1, 2, 3, 4, 5] } let a, b, c; [a, ...b] = f(); console.log(a, b);}//output: 1 [2, 3, 4, 5]

{ let o={p:42, q:true}; let {p, q, c=5} = o; console.log(p ,q);}//output: 42 true 5

{ let metaData={  title: 'abc',  test: [{   title: 'test',   desc: 'description'  }] } let {title:esTitle, test:[{title:cnTitle}]} = metaData; console.log(esTitle, cnTitle);}//Output: abc test