JavaScript 解构:数组和对象的简化处理
ES6 引入的 JavaScript 解构功能,让数组和对象数据的提取和赋值变得高效便捷。它提升了代码的可读性和简洁性。
数组解构将数组元素直接赋值给变量:
const numbers = [1, 2, 3, 4]; const [x, y, z] = numbers; console.log(x); // 输出:1 console.log(y); // 输出:2 console.log(z); // 输出:3
跳过元素
使用逗号占位符跳过数组元素:
const numbers = [1, 2, 3, 4]; const [x, , z] = numbers; console.log(x); // 输出:1 console.log(z); // 输出:3
默认值
为缺失元素设置默认值:
const numbers = [1]; const [x, y = 2] = numbers; console.log(x); // 输出:1 console.log(y); // 输出:2
对象解构将对象属性赋值给变量,使用花括号 {}:
const person = { firstName: "John", age: 30, city: "New York" }; const { firstName, age, city } = person; console.log(firstName); // 输出:John console.log(age); // 输出:30 console.log(city); // 输出:New York
重命名变量
解构时可重命名变量:
const person = { firstName: "John", age: 30 }; const { firstName: name, age: years } = person; console.log(name); // 输出:John console.log(years); // 输出:30
默认值
为对象属性设置默认值:
const person = { firstName: "John" }; const { firstName, age = 25 } = person; console.log(firstName); // 输出:John console.log(age); // 输出:25
嵌套对象解构
解构嵌套对象:
const person = { firstName: "John", address: { city: "New York", zip: "10001" } }; const { firstName, address: { city, zip } } = person; console.log(firstName); // 输出:John console.log(city); // 输出:New York console.log(zip); // 输出:10001
在函数参数中直接使用解构:
数组解构
function showCoords([x, y]) { console.log(`x: ${x}, y: ${y}`); } const coords = [10, 20]; showCoords(coords); // 输出:x: 10, y: 20
对象解构
function showPerson({ firstName, age }) { console.log(`Name: ${firstName}, Age: ${age}`); } const person = { firstName: "Jane", age: 25 }; showPerson(person); // 输出:Name: Jane, Age: 25
剩余运算符 (…) 收集剩余元素或属性:
数组
const numbers = [1, 2, 3, 4]; const [first, ...rest] = numbers; console.log(first); // 输出:1 console.log(rest); // 输出: [2, 3, 4]
对象
const person = { firstName: "John", age: 30, city: "New York" }; const { firstName, ...rest } = person; console.log(firstName); // 输出:John console.log(rest); // 输出: { age: 30, city: 'New York' }
总结
JavaScript 解构简化了数组和对象的操作,使代码更易读、更清晰。 尤其在处理复杂数据结构和函数参数时,其优势更为明显。
标签: JS
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