Without further ado, let’s start with a piece of code (reprinted from "JavaScript Design Patterns and Development Practices")
//谷歌地图show方法 var googleMap = { googlShow: function() { console.log("谷歌地图"); } }; //百度地图show方法 var baiduMap = { baiduShow: function() { console.log("百度地图"); } }; //渲染地图函数 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
Regarding the questions raised in the book, it is assumed that the name of the method for displaying maps provided by each map API is show. In actual development Maybe it won't go so smoothly. The idea proposed by the author in the book is to use the adapter pattern to solve the problem. The following is what I improved after imitating the adapter pattern:
var googleMap = { googlShow: function() { console.log("谷歌地图"); } }; var baiduMap = { baiduShow: function() { console.log("百度地图"); } }; //适配器参数配置 var mapArg = { "googleMap": googleMap.googlShow, "baiduMap": baiduMap.baiduShow }; //适配器地图 var adaptMap = { show: function(arg) { for (var imap in mapArg) { for (var fmap in arg) { if (imap && fmap && mapArg[imap].name==fmap) { return mapArg[imap](); } } } } }; //只关注发出显示地图而不关注具体用哪种地图 var renderMap = function(arg) { adaptMap.show(arg); }; //当增加了搜搜地图,我们需要添加搜搜地图的方法以及修改适配器地图参数 //而不需要对renderMap函数进行修改 var sosoMap = { sosoShow: function() { console.log("搜搜地图"); } }; mapArg.sosoMap=sosoMap.sosoShow; render(sosoMap);

Python and JavaScript have their own advantages and disadvantages in terms of community, libraries and resources. 1) The Python community is friendly and suitable for beginners, but the front-end development resources are not as rich as JavaScript. 2) Python is powerful in data science and machine learning libraries, while JavaScript is better in front-end development libraries and frameworks. 3) Both have rich learning resources, but Python is suitable for starting with official documents, while JavaScript is better with MDNWebDocs. The choice should be based on project needs and personal interests.

The shift from C/C to JavaScript requires adapting to dynamic typing, garbage collection and asynchronous programming. 1) C/C is a statically typed language that requires manual memory management, while JavaScript is dynamically typed and garbage collection is automatically processed. 2) C/C needs to be compiled into machine code, while JavaScript is an interpreted language. 3) JavaScript introduces concepts such as closures, prototype chains and Promise, which enhances flexibility and asynchronous programming capabilities.

Different JavaScript engines have different effects when parsing and executing JavaScript code, because the implementation principles and optimization strategies of each engine differ. 1. Lexical analysis: convert source code into lexical unit. 2. Grammar analysis: Generate an abstract syntax tree. 3. Optimization and compilation: Generate machine code through the JIT compiler. 4. Execute: Run the machine code. V8 engine optimizes through instant compilation and hidden class, SpiderMonkey uses a type inference system, resulting in different performance performance on the same code.

JavaScript's applications in the real world include server-side programming, mobile application development and Internet of Things control: 1. Server-side programming is realized through Node.js, suitable for high concurrent request processing. 2. Mobile application development is carried out through ReactNative and supports cross-platform deployment. 3. Used for IoT device control through Johnny-Five library, suitable for hardware interaction.

I built a functional multi-tenant SaaS application (an EdTech app) with your everyday tech tool and you can do the same. First, what’s a multi-tenant SaaS application? Multi-tenant SaaS applications let you serve multiple customers from a sing

This article demonstrates frontend integration with a backend secured by Permit, building a functional EdTech SaaS application using Next.js. The frontend fetches user permissions to control UI visibility and ensures API requests adhere to role-base

JavaScript is the core language of modern web development and is widely used for its diversity and flexibility. 1) Front-end development: build dynamic web pages and single-page applications through DOM operations and modern frameworks (such as React, Vue.js, Angular). 2) Server-side development: Node.js uses a non-blocking I/O model to handle high concurrency and real-time applications. 3) Mobile and desktop application development: cross-platform development is realized through ReactNative and Electron to improve development efficiency.

The latest trends in JavaScript include the rise of TypeScript, the popularity of modern frameworks and libraries, and the application of WebAssembly. Future prospects cover more powerful type systems, the development of server-side JavaScript, the expansion of artificial intelligence and machine learning, and the potential of IoT and edge computing.


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