Many popular libraries and frameworks use plug-in systems such as WordPress, jQuery, Gatsby, Eleventy, and Vue. The plug-in system allows developers to add features in a secure and scalable way, enhancing the value of core projects and building communities while reducing maintenance burdens. This article will explain its design concept by building a JavaScript plug-in system.
We will take an example of a simple JavaScript calculator called BetaCalc, with the goal of allowing other developers to add a "button" feature to it.
Initial calculator code:
// Calculator const betaCalc = { currentValue: 0, setValue(newValue) { this.currentValue = newValue; console.log(this.currentValue); }, plus(addend) { this.setValue(this.currentValue addend); }, minus(subtrahend) { this.setValue(this.currentValue - subtrahend); } }; // Use calculator betaCalc.setValue(3); // => 3 betaCalc.plus(3); // => 6 betaCalc.minus(2); // => 4
This calculator has limited functionality and can only display results through console.log
. Next, we will add the plugin system.
The simplest plug-in system:
We first create a register
method that allows developers to register plugins. This method takes the plugin, gets its exec
function, and attaches it to the calculator as a new method:
// Calculator const betaCalc = { // ...Other calculator code register(plugin) { const { name, exec } = plugin; this[name] = exec; } };
An example of a simple "square" button plugin:
// Define the plugin const squaredPlugin = { name: 'squared', exec: function() { this.setValue(this.currentValue * this.currentValue); } }; // Register plugin betaCalc.register(squaredPlugin);
Plugins usually contain two parts: code and metadata (name, description, version number, dependencies, etc.). In this example, the exec
function contains code and name
is metadata. After registration, exec
function is directly attached to betaCalc
object as a method.
Now, BetaCalc has a new "squared" button:
betaCalc.setValue(3); // => 3 betaCalc.plus(2); // => 5 betaCalc.squared(); // => 25 betaCalc.squared(); // => 625
This method is simple and easy to use, and the plug-in can be easily distributed and imported through npm. But it also has flaws: the plugin directly accesses this
in betaCalc
, has permission to read and write all code, and violates the principle of opening and closing. In addition, the squared
function works through side effects and is not ideal.
Improved plug-in architecture:
To solve these problems, we improve the plug-in architecture:
// Calculator const betaCalc = { currentValue: 0, setValue(value) { this.currentValue = value; console.log(this.currentValue); }, core: { 'plus': (currentVal, addend) => currentVal addend, 'minus': (currentVal, subtrahend) => currentVal - subtrahend }, plugins: {}, press(buttonName, newVal) { const func = this.core[buttonName] || this.plugins[buttonName]; this.setValue(func(this.currentValue, newVal)); }, register(plugin) { const { name, exec } = plugin; this.plugins[name] = exec; } }; // Plugin const squaredPlugin = { name: 'squared', exec: function(currentValue) { return currentValue * currentValue; } }; betaCalc.register(squaredPlugin); // Use calculator betaCalc.setValue(3); // => 3 betaCalc.press('plus', 2); // => 5 betaCalc.press('squared'); // => 25 betaCalc.press('squared'); // => 625
Improvements:
- Separate the plugin from the core method and store it in the
plugins
object to improve security. - Use the
press
method to find functions and call them by name, convert buttons into pure functions, simplifying API, convenient testing, and reducing coupling.
This architecture is more limited, but safer and more reliable. It may be too strict, limiting the functionality extension of the plugin. The permissions of plug-in authors need to be carefully weighed, which not only ensures the stability of the project, but also allows them to solve problems.
Further improvements:
It can be further improved: add error handling, extend plug-in functions (such as registration lifecycle callbacks, storage status, etc.), and improve plug-in registration mechanism (supports batch registration, configuration settings, etc.).
Summarize:
Building an excellent plug-in system is not easy, and requires careful consideration of various factors. Only by referring to the plug-in system of existing projects (such as jQuery, Gatsby, etc.) and JavaScript design patterns, and following software development principles (such as open and shutdown principles, loose coupling, Dimitter rules, dependency injection), can we build a plug-in system that meets all user needs in the long term. A good plug-in system can promote the prosperity of the developer community and achieve a win-win situation.
The above is the detailed content of Designing a JavaScript Plugin System. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undress AI Tool
Undress images for free

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics









CSS blocks page rendering because browsers view inline and external CSS as key resources by default, especially with imported stylesheets, header large amounts of inline CSS, and unoptimized media query styles. 1. Extract critical CSS and embed it into HTML; 2. Delay loading non-critical CSS through JavaScript; 3. Use media attributes to optimize loading such as print styles; 4. Compress and merge CSS to reduce requests. It is recommended to use tools to extract key CSS, combine rel="preload" asynchronous loading, and use media delayed loading reasonably to avoid excessive splitting and complex script control.

Autoprefixer is a tool that automatically adds vendor prefixes to CSS attributes based on the target browser scope. 1. It solves the problem of manually maintaining prefixes with errors; 2. Work through the PostCSS plug-in form, parse CSS, analyze attributes that need to be prefixed, and generate code according to configuration; 3. The usage steps include installing plug-ins, setting browserslist, and enabling them in the build process; 4. Notes include not manually adding prefixes, keeping configuration updates, prefixes not all attributes, and it is recommended to use them with the preprocessor.

TocreatestickyheadersandfooterswithCSS,useposition:stickyforheaderswithtopvalueandz-index,ensuringparentcontainersdon’trestrictit.1.Forstickyheaders:setposition:sticky,top:0,z-index,andbackgroundcolor.2.Forstickyfooters,betteruseposition:fixedwithbot

Theconic-gradient()functioninCSScreatescirculargradientsthatrotatecolorstopsaroundacentralpoint.1.Itisidealforpiecharts,progressindicators,colorwheels,anddecorativebackgrounds.2.Itworksbydefiningcolorstopsatspecificangles,optionallystartingfromadefin

The scope of CSS custom properties depends on the context of their declaration, global variables are usually defined in :root, while local variables are defined within a specific selector for componentization and isolation of styles. For example, variables defined in the .card class are only available for elements that match the class and their children. Best practices include: 1. Use: root to define global variables such as topic color; 2. Define local variables inside the component to implement encapsulation; 3. Avoid repeatedly declaring the same variable; 4. Pay attention to the coverage problems that may be caused by selector specificity. Additionally, CSS variables are case sensitive and should be defined before use to avoid errors. If the variable is undefined or the reference fails, the fallback value or default value initial will be used. Debug can be done through the browser developer

Mobile-firstCSSdesignrequiressettingtheviewportmetatag,usingrelativeunits,stylingfromsmallscreensup,optimizingtypographyandtouchtargets.First,addtocontrolscaling.Second,use%,em,orreminsteadofpixelsforflexiblelayouts.Third,writebasestylesformobile,the

There are three ways to create a CSS loading rotator: 1. Use the basic rotator of borders to achieve simple animation through HTML and CSS; 2. Use a custom rotator of multiple points to achieve the jump effect through different delay times; 3. Add a rotator in the button and switch classes through JavaScript to display the loading status. Each approach emphasizes the importance of design details such as color, size, accessibility and performance optimization to enhance the user experience.

To make the entire grid layout centered in the viewport, it can be achieved by the following methods: 1. Use margin:0auto to achieve horizontal centering, and the container needs to be set to set the fixed width, which is suitable for fixed layout; 2. Use Flexbox to set the justify-content and align-items properties in the outer container, and combine min-height:100vh to achieve vertical and horizontal centering, which is suitable for full-screen display scenarios; 3. Use CSSGrid's place-items property to quickly center on the parent container, which is simple and has good support from modern browsers, and at the same time, it is necessary to ensure that the parent container has sufficient height. Each method has applicable scenarios and restrictions, just choose the appropriate solution according to actual needs.
