TypeScript Tips: Extend HTML Element Properties
This article is excerpted from "Releasing the Power of TypeScript", which will show you how to extend the properties of HTML elements in TypeScript. In large applications, we often build components based on standard HTML elements, such as custom buttons, or components that combine tags and input fields.
TypeScript requires explicit definition of properties accepted by the component, which can be cumbersome for each property. To match the attributes used by HTML elements in React, you can use React.ComponentProps
. To exclude certain properties, you can use the Omit
utility type.
To extend the properties of a component, you can use the intersection type. This allows the component to accept all attributes of the HTML element as well as other additional attributes. This is useful for components that change styles based on the current theme or add new features to standard HTML elements.
Method 1: Extend the properties of a single HTML element
Let's create a custom button component with in-app style. In JavaScript, we can do this:
const Button = (props) => { return <button {...props} />; };
In TypeScript, we can add necessary properties, such as children
:
const Button = ({ children }: React.PropsWithChildren) => { return <button>{children}</button>; };
But this is very cumbersome. We can use React.ComponentProps
to match the attributes of HTML button
elements:
const Button = (props: React.ComponentProps<'button'>) => { return <button {...props} />; };
But if the user passes the className
property, it overwrites our style. We can use Omit
to exclude specific attributes:
type ButtonProps = Omit<React.ComponentProps<'button'>, 'className'>; const Button = (props: ButtonProps) => { return <button {...props} />; };
Or, we can use the clsx
library to manage class names:
import React from 'react'; import clsx from 'clsx'; type ButtonProps = React.ComponentProps<'button'>; const Button = ({ className, ...props }: ButtonProps) => { return <button className={clsx('button', className)} {...props} />; };
To extend the attribute, you can use the intersection type:
type ButtonProps = React.ComponentProps<'button'> & { variant?: 'primary' | 'secondary'; };
The Button
component now accepts all attributes of the button
element, as well as additional variant
attributes.
Method 2: Create a composite component
Another common component is the component that combines labels and input elements:
type LabeledInputProps = React.ComponentProps<'input'> & { label: string; }; const LabeledInput = ({ id, label, ...props }: LabeledInputProps) => { return ( <> <label htmlFor={id}>{label}</label> <input id={id} {...props} /> </> ); };
This way, we can easily reuse and extend the functionality of standard HTML elements, improving the maintainability and reusability of our code.
This article is excerpted from "Releasing the Power of TypeScript". For more information, please visit SitePoint Premium or e-book retailer.
The above is the detailed content of Extending the Properties of an HTML Element in TypeScript. 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











PlacingtagsatthebottomofablogpostorwebpageservespracticalpurposesforSEO,userexperience,anddesign.1.IthelpswithSEObyallowingsearchenginestoaccesskeyword-relevanttagswithoutclutteringthemaincontent.2.Itimprovesuserexperiencebykeepingthefocusonthearticl

The following points should be noted when processing dates and time in JavaScript: 1. There are many ways to create Date objects. It is recommended to use ISO format strings to ensure compatibility; 2. Get and set time information can be obtained and set methods, and note that the month starts from 0; 3. Manually formatting dates requires strings, and third-party libraries can also be used; 4. It is recommended to use libraries that support time zones, such as Luxon. Mastering these key points can effectively avoid common mistakes.

Event capture and bubble are two stages of event propagation in DOM. Capture is from the top layer to the target element, and bubble is from the target element to the top layer. 1. Event capture is implemented by setting the useCapture parameter of addEventListener to true; 2. Event bubble is the default behavior, useCapture is set to false or omitted; 3. Event propagation can be used to prevent event propagation; 4. Event bubbling supports event delegation to improve dynamic content processing efficiency; 5. Capture can be used to intercept events in advance, such as logging or error processing. Understanding these two phases helps to accurately control the timing and how JavaScript responds to user operations.

There are three common ways to initiate HTTP requests in Node.js: use built-in modules, axios, and node-fetch. 1. Use the built-in http/https module without dependencies, which is suitable for basic scenarios, but requires manual processing of data stitching and error monitoring, such as using https.get() to obtain data or send POST requests through .write(); 2.axios is a third-party library based on Promise. It has concise syntax and powerful functions, supports async/await, automatic JSON conversion, interceptor, etc. It is recommended to simplify asynchronous request operations; 3.node-fetch provides a style similar to browser fetch, based on Promise and simple syntax

The main difference between ES module and CommonJS is the loading method and usage scenario. 1.CommonJS is synchronously loaded, suitable for Node.js server-side environment; 2.ES module is asynchronously loaded, suitable for network environments such as browsers; 3. Syntax, ES module uses import/export and must be located in the top-level scope, while CommonJS uses require/module.exports, which can be called dynamically at runtime; 4.CommonJS is widely used in old versions of Node.js and libraries that rely on it such as Express, while ES modules are suitable for modern front-end frameworks and Node.jsv14; 5. Although it can be mixed, it can easily cause problems.

JavaScript's garbage collection mechanism automatically manages memory through a tag-clearing algorithm to reduce the risk of memory leakage. The engine traverses and marks the active object from the root object, and unmarked is treated as garbage and cleared. For example, when the object is no longer referenced (such as setting the variable to null), it will be released in the next round of recycling. Common causes of memory leaks include: ① Uncleared timers or event listeners; ② References to external variables in closures; ③ Global variables continue to hold a large amount of data. The V8 engine optimizes recycling efficiency through strategies such as generational recycling, incremental marking, parallel/concurrent recycling, and reduces the main thread blocking time. During development, unnecessary global references should be avoided and object associations should be promptly decorated to improve performance and stability.

The difference between var, let and const is scope, promotion and repeated declarations. 1.var is the function scope, with variable promotion, allowing repeated declarations; 2.let is the block-level scope, with temporary dead zones, and repeated declarations are not allowed; 3.const is also the block-level scope, and must be assigned immediately, and cannot be reassigned, but the internal value of the reference type can be modified. Use const first, use let when changing variables, and avoid using var.

The main reasons for slow operation of DOM are the high cost of rearrangement and redrawing and low access efficiency. Optimization methods include: 1. Reduce the number of accesses and cache read values; 2. Batch read and write operations; 3. Merge and modify, use document fragments or hidden elements; 4. Avoid layout jitter and centrally handle read and write; 5. Use framework or requestAnimationFrame asynchronous update.
