个人建设网站,建筑网上接活平台,有网站建wap,网站建设招标流程解构赋值语法是一个 Javascript 表达式,这使得可以将值从数组或属性从对象提取到不同的变量中。
数组解构赋值#xff1a; {let a,b,rest;[a,b][1,2];console.log(a,b); //1 2 } {let a,b,rest;[a,b,...rest][1,2,3,4,5]; console.log(a,b,rest); //1 2 [ 3, 4, 5 ]…解构赋值语法是一个 Javascript 表达式,这使得可以将值从数组或属性从对象提取到不同的变量中。
数组解构赋值 {let a,b,rest;[a,b][1,2];console.log(a,b); //1 2 } {let a,b,rest;[a,b,...rest][1,2,3,4,5]; console.log(a,b,rest); //1 2 [ 3, 4, 5 ]} {let a,b;({a,b}{a:1,b:2})console.log(a,b); //1 2
} {let a,b,rest;[a,b,c3][1,2];console.log(a,b,c); //1 2 3
} let a,b,rest;[a,b,c][1,2];console.log(a,b,c); //1 2 undefined
} 数组解构赋值的应用 //变量交换
{let a1,b2;[a,b][b,a];console.log(a,b); //2 1
} //分别取多个返回值很方便
{function f(){return[1,2]}let a,b;[a,b]f();console.log(a,b); // 1 2
} //选择性的接受需要的值
{function f(){return[1,2,3,4,5]}let a,b;[a,,,b]f();console.log(a,b); // 1 4
} //不知函数返回值的长度只想取得想要的值
{function f(){return[1,2,3,4,5]}let a,b;[a,...b]f();console.log(a,b); // 1 [2,3,4,5]
} {function f(){return[1,2,3,4,5]}let a,b;[a,,...b]f();console.log(a,b); // 1 [3,4,5]
} 对象的解构赋值 {let obj{a:2,b:true}let {a,b}obj;console.log(a,b); //2 true
} {
//对象const people {name: lux,age: 20}const {age,name} people
//必须为nameage,即原属性名;其顺序可以改变相应的值不变console.log(${name} --- ${age})
// lux --- 20
} {let obj{a:2,b:true}let {c,d}obj;console.log(c,d); //undefined undefined
} {let {a3,b5}{a:4}console.log(a,b); //4 5
}
{let {a:c,b:d}{a:4,b:5}console.log(c,d); //4 5
} 对象解构赋值的应用 {let metaData{title:abc,test:[{title:test,desc:description}]}let {title:esTitle,test:[{title:cnTitle}]}metaData; //test:[{title:cnTitle}]必须和原来的形式一模一样console.log(esTitle,cnTitle); //abc test
} //错误应用
{let metaData{title:abc,test:[{title:test,desc:description}]}let {title,test:[{titl}]}metaData;console.log(title,test:[{titl}]); //报错test:[{titl}])} 更多专业前端知识请上
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