ES6 解构

数组

从数组中取元素

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const names = ['Luke', 'Eva', 'Phil'];
const [first] = names;
console.log(first); // 'Luke'
const [first, second] = names;
console.log(first, second); // 'Luke' 'Eva'

元素缺失时的默认值

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const [first, second, third, fourth='Martin'] = names;
console.log(fourth); // 'Martin'

跳过数组中的元素

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var [first, , second] = names;
console.log(first, second); // 'Luke' 'Phil'

分配数组中剩下的给某元素

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var [first, ...rest] = names;
console.log(rest); // ['Eva','Phil']

对象

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const person = {
  name: 'Luke',
  age: '24',
  facts: {
    hobby: 'Photo',
    work: 'Software Developer'
  }
}

从对象中提取数据

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const {name, age} = person;
console.log(name, age); // 'Luke' '24'

提取嵌套值

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const {facts: {hobby}} = person;
console.log(hobby); // 'Photo'

数据缺失时的默认值

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const {hometown = 'Unknown'} = person;
console.log(hometown); // 'Unknown'

解构函数参数

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const toString = ({name, age}) => {
  return `${name} is ${age} years old`;
}
toString(person); // Luke is 24 years old