ES6: 对象和数组解构

所谓解构，指的是将数据结构分解为更小的部分，从而使数据提取变得容易。 对象解构：

• 使用解构时，必须提供初始化值 let Person = { name: 'sen', age: 18 } let {name, age} = Person;
• 解构表达式的值为=右侧的值
• 如果对象中没有同名属性时，解构表达式新赋值的变量的值为undefined
• 解构对象只是赋值时，需要加()
• 赋值给不同名的变量 let Person = { name: 'sen', age: 18 } let {name: localName, age: localAge} = Person;
• 设置默认值 let Person = { name: 'sen', age: 18 } let {name, age: localAge = 18} = Person;
• 嵌套解构 let Person = { name: 'sen', age: 18, score: { maths: 100 } } let {name, score: {maths}} = Person; console.log(maths);

数组解构

• let score = [99, 88, 77]; let [maths, english, chinese] = score; [,,chinese] = score;
• 数组解构赋值不需要加() let a = 3; let b = 4; [a, b] = [b, a]
• 嵌套的解构 let score = [99, 88, [77]]; let [,,[chinese]] = score;
• 剩余项 let score = [99, 88, 77]; let [maths, ...restScore] = score; console.log(restScore) // [88, 77]
• 数组和对象可以混合解构let Person = { name: 'sen', age: [0, 18] } let {name: localName, age: [start]} = Person; console.log(start);