18 个基本 JavaScript 方法代码片段
web前端开发
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2024-06-19 20:15
在我们的日常开发过程中,我们经常使用许多常见的 JavaScript 代码片段,例如复制内容或从 URL 中检索特定参数。
这些代码片段都有固定的实现,方便开发,今天我们来了解一下7个常用的代码片段。
01、函数节流
/** Function throttling timer version */
function throttle(callback: Function, delay: number) {
let timer: number | null
return function () {
if (timer) return
const args = arguments //Use closure to save parameter array
timer = setTimeout(() => {
callback.apply(null, args)
timer = null
}, delay)
}
}
02、URL 解码和编码
/** Encode URL */
function encodeURL(url: string, isComponent = true): string {
return isComponent ? encodeURIComponent(url) : encodeURI(url)
}
/** Decode URL */
function decodeURL(url: string, isComponent = true): string {
return isComponent ? decodeURIComponent(url) : decodeURI(url)
}
03、使用JavaScript 获取全局 CSS 变量
/**
* @description Use JS to get global css variables
* @param cssVariableName variable name
* @returns {string} variable value
*/
function getCssVariableValue(cssVariableName: string): string {
return getComputedStyle(document.documentElement).getPropertyValue(cssVariableName)
}
04、使用 JS 设置全局 CSS 变量
/**
* @description Set global CSS variables with JS
* @param {string} cssVariableName variable name
* @param {string} cssVariableValue variable value
*/
function setCssVariableValue(cssVariableName: string, cssVariableValue: string): void {
document.documentElement.style.setProperty(cssVariableName, cssVariableValue)
}
05、清除所有 cookies
/**
* @description clear all cookies
*/
function clearCookie(): void {
const keyList = document.cookie.match(/[^ =;]+(?=\=)/g) as string[] | null
keyList && keyList.forEach(key => (document.cookie = `${key}=0;path=/;expires=${new Date(0).toUTCString()}`))
}
06、清除所有项目缓存
/**
* @description Clear all project caches
*/
function clearCache(): void {
window.localStorage.clear()
window.sessionStorage.clear()
const keyList = document.cookie.match(/[^ =;]+(?=\=)/g) as string[] | null
keyList && keyList.forEach(key => (document.cookie = `${key}=0;path=/;expires=${new Date(0).toUTCString()}`))
}
07、通过名称获取 URL 查询参数
/**
* @description Get URL query parameters by name
* @param {string} key The key of the query parameter that needs to be obtained
* @param {string} url The link that needs to be parsed, the default is window.location.href
* @returns {string | null} obtained value corresponding to key
*/
function getQueryByName(key, url = window.location.href) {
const queryNameRegExp = new RegExp(`[?&]${key}=([^&]*)(?:&|$)`)
const queryNameMatch = url.match(queryNameRegExp)
return queryNameMatch ? decodeURIComponent(queryNameMatch[1]) : null
}
08、登录页面时间前缀
/**
* @description time prefix of login page
* @returns {string} time prefix
*/
function timeFix(): string {
const time = new Date()
const hour = time.getHours()
return hour < 9 ? 'Good morning' : hour <= 11 ? 'Good morning' : hour <= 13 ? 'Good afternoon' : hour < 20 ? 'Good afternoon' : 'Good evening'
}
09、登录页面上的欢迎信息
/**
* @description Welcome message on the login page
* @returns {string} random welcome message
*/
function welcome(): string {
const list = ['Long time no see, I miss you so much! ', 'Wait until the stars go to sleep before I miss you', 'We are open today']
return list[Math.floor(Math.random() * list.length)]
}
10、递归深层复制
/**
* @description Make a deep copy of the incoming data and return it
* @param {any} source data source
* @returns {any} copied data
*/
function deepClone(source: any): any {
if (!source || typeof source !== 'object') return source
if (source instanceof Date) return new Date(source)
if (source instanceof RegExp) return new RegExp(source)
const target = Array.isArray(source) ? ([] as Record<any, any>) : ({} as Record<any, any>)
for (const key in source) target[key] = typeof source[key] === 'object' ? deepClone(source[key]) : source[key]
return target
}
11、随机生成一个 UUID
/**
* @description Randomly generate a UUID
* @returns {string} generated uuid
*/
function getRandomUUID(): string {
const tempURL = URL.createObjectURL(new Blob())
const uuidStr = tempURL.toString()
const separator = uuidStr.includes('/') ? '/' : ':'
URL.revokeObjectURL(tempURL)
return uuidStr.substring(uuidStr.lastIndexOf(separator) + 1)
}
function getRandomUUID(): string {
const fn = (): string => (((1 + Math.random()) * 0x10000) | 0).toString(16).substring(1)
return fn() + fn() + '-' + fn() + '-' + fn() + '-' + fn() + '-' + fn() + fn() + fn()
}
12、随机布尔值
/**
* @description random boolean value
* @returns {boolean} true | false
*/
function getRandomBoolean(): boolean {
return Math.random() > 0.5
}
13、反转字符串
/**
* @description reverse string
* @param {string} str string
* @returns {string} reversed string
*/
function reverseString(str: string): string {
return str.split('').reverse().join('')
}
14、随机生成十六进制颜色
/**
* @description Randomly generates a color string in Hex format
* @returns {string} Color string in Hex format
*/
function getRandomHexColor(): string {
return `#${Math.floor(Math.random() * 0xffffff).toString(16)}`
}
15、获取变量的真实类型
/**
* @description Get the real type of the variable
* @param {any} variable variable of any type
* @returns {string} variable type
*/
function getRawType(variable: any): string {
return Object.prototype.toString.call(variable).split(' ')[1].replace(']', '').toLowerCase()
}
16、将文本复制到剪贴板
/**
* @description Copy text to clipboard
* @param {string} text The copied text
*/
function copyText(text: string): void {
// Whether to support navigator.clipboard attribute
const isClipboardApiSupported = window.navigator && window.navigator.clipboard
if (isClipboardApiSupported) {
window.navigator.clipboard.writeText(text)
} else {
const textarea = document.createElement('textarea')
textarea.readOnly = true
textarea.value = text
textarea.style.position = 'absolute'
textarea.style.top = '-9999px'
textarea.style.left = '-9999px'
document.body.appendChild(textarea)
textarea.select()
document.execCommand('copy')
textarea.remove()
}
}
17、滚动到顶部
/**
* @description scroll to top
*/
function scrollToTop(element: HTMLElement): void {
element.scrollIntoView({ behavior: 'smooth', block: 'start' })
}
18、对象通用方法
const obj = { a: 1, b: 2, c: 3, d: 4 }
//Object.keys()
// Will return an array consisting of the given object's own enumerable properties
Object.keys(obj) // ['a', 'b', 'c', 'd']
//Object.values()
// Returns an array of all enumerable property values of the given object itself
Object.values(obj) // [1, 2, 3, 4]
//Object.entries()
// Returns an array of key-value pairs for the given object's own enumerable properties
Object.entries(obj) // [['a', 1], ['b', 2], ['c', 3], ['d', 4]]
//Object.fromEntries()
//Convert the list of key-value pairs into an object, which is the reverse operation of Object.entries()
Object.fromEntries( [['a', 1], ['b', 2]]) // { a: 1, b: 2 }
// hasOwnProperty()
// Returns a Boolean value indicating whether the object has the specified attribute in its own properties (that is, whether it has the specified key)
obj.hasOwnProperty('a') // true
obj.hasOwnProperty('fff') // false
//Object.assign()
// Used to copy the values of all enumerable properties from one or more source objects to the target object. It will return the target object.
const target = { a: 1, b: 2 }
const source = { b: 4, c: 5 }
const result = Object.assign(target, source) // { ...target, ...source } has the same effect
console.log(result) // {a: 1, b: 4, c: 5}
总结
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最后,感谢你的阅读,祝编程愉快!
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