31.对象方法的扩展

2023-10-11 08:06:04

<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8" /> <meta http-equiv="X-UA-Compatible" content="IE=edge" /> <meta name="viewport" content="width=device-width, initial-scale=1.0" /> <title>Document</title> </head> <body> <script> // 1.Object.is 判断两个值是否完全相等,类似于===,但是又不太一样,比如NaN===NaN // console.log(Object.is(120, 100)); // console.log(Object.is(NaN, NaN)); // console.log(NaN === NaN); // console.log(NaN !== NaN);
// 2.Object.assign 对象的合并---也可用于对象的浅拷贝 let config1 = { host: "localhost", port: 3306, name: "root", password: "root", test1: "测试1", };
let config2 = { host: "https://www.baidu.com", port: 33060, name: "百度", password: 123, test2: "测试2", }; console.log(Object.assign(config1, config2)); //后面对象里的属性会把前面对象里同名的属性覆盖掉,不相同的则保留
// 3.Object.setPrototypeOf,Object.getPrototypeOf let school = { name: "xxx", };
let cities = { address: ["xx1", "xx2", "xx3"], };
// 此方法不建议这样做,应该在创建对象的时候就把原型设置好,效率高 Object.create(proto, [propertiesObject]) Object.setPrototypeOf(school, cities); //为school设置原型对象为cities console.log(school); console.log(Object.getPrototypeOf(school)); </script> </body> </html>

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