This article introduces polymorphism in JS to you in detail through example code. Friends who are interested in JS should take a look at this article for a detailed explanation of polymorphism examples in JS
Polymorphism inObject-orientedProgramming language is very important. In JAVA, polymorphism is achieved through inheritance. As follows:
public abstract class Animal { abstract void makeSound(); // 抽象方法 } public class Chicken extends Animal{ public void makeSound(){ System.out.println( "咯咯咯" ); } } public class Duck extends Animal{ public void makeSound(){ System.out.println( "嘎嘎嘎" ); } } Animal duck = new Duck(); // (1) Animal chicken = new Chicken(); // (2)
The idea of polymorphism is actually to separate "what to do" and "who to do it". To achieve this, in the final analysis, we must first eliminate the coupling relationship between types.
In Java, polymorphism can be achieved through upward transformation. The javascript variables are variable during runtime. A js object can represent both a Duck type object and a Chicken type object, which means JavaScript Object## The polymorphism of # is inherent.
var googleMap = { show: function(){ console.log( '开始渲染谷歌地图' ); } }; var renderMap = function(){ googleMap.show(); }; renderMap(); // 输出:开始渲染谷歌地图 var googleMap = { show: function(){ console.log( '开始渲染谷歌地图' ); } }; var baiduMap = { show: function(){ console.log( '开始渲染百度地图' ); } }; var renderMap = function( type ){ if ( type === 'google' ){ googleMap.show(); }else if ( type === 'baidu' ){ baiduMap.show(); } }; renderMap( 'google' ); // 输出:开始渲染谷歌地图 renderMap( 'baidu' ); // 输出:开始渲染百度地图
var renderMap = function( map ){ if ( map.show instanceof Function ){ map.show(); } }; renderMap( googleMap ); // 输出:开始渲染谷歌地图 renderMap( baiduMap ); // 输出:开始渲染百度地图
var TencentMap = { show: function(){ console.log( '开始渲染腾讯地图' ); } } renderMap( sosoMap ); // 输出:开始渲染腾讯地图
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