03 Snippets

001 Fisher–Yates Shuffle 洗牌算法
const shuffle = (arr) => {
  let i = arr.length
  let j
  while (i) {
    j = Math.floor(Math.random() * i--)
    ;[arr[i], arr[j]] = [arr[j], arr[i]]
  }
  return arr
}
002 数字千分位格式化
const toThousandFilter = (num) => num.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ',')
003 日期格式化
const parseTime = (time, format = '{y}-{m}-{d} {h}:{i}:{s}') => {
  if (arguments.length === 0) return null
  let date
  if (typeof time === 'object') {
    date = time
  } else {
    if (typeof time === 'string' && /^[0-9]+$/.test(time)) {
      time = parseInt(time)
    }
    if (typeof time === 'number' && time.toString().length === 10) {
      time = time * 1000
    }
    date = new Date(time)
  }
  const formatObj = {
    y: date.getFullYear(),
    m: date.getMonth() + 1,
    d: date.getDate(),
    h: date.getHours(),
    i: date.getMinutes(),
    s: date.getSeconds(),
    a: date.getDay(),
  }
  const time_str = format.replace(/{(y|m|d|h|i|s|a)+}/g, (result, key) => {
    let value = formatObj[key]
    // Note: getDay() returns 0 on Sunday
    if (key === 'a') {
      return ['日', '一', '二', '三', '四', '五', '六'][value]
    }
    if (result.length > 0 && value < 10) {
      value = '0' + value
    }
    return value || 0
  })
  return time_str
}
004 动态加载 JS 文件
const loadJS = (url) => {
  return new Promise((resolve) => {
    const recaptchaScript = document.createElement('script')
    recaptchaScript.setAttribute('src', url)
    recaptchaScript.async = true
    recaptchaScript.onload = () => resolve()
    document.head.appendChild(recaptchaScript)
  })
}
​
const loadAssets = async () => {
  const assets = [
    'https://cdnjs.cloudflare.com/ajax/libs/jquery/3.4.0/jquery.min.js',
    'https://cdnjs.cloudflare.com/ajax/libs/jqueryui/1.12.1/jquery-ui.min.js',
  ]
​
  for (const url of assets) {
    await loadJS(url)
  }
}
005 动态下载文件
const downloadFile = (file) => {
  fetch(file.url).then((res) =>
    res.blob().then((blob) => {
      const a = document.createElement('a')
      const url = window.URL.createObjectURL(blob)
      a.href = url
      a.download = file.name
      a.click()
      window.URL.revokeObjectURL(url)
    })
  )
}
006 获取文件扩展名
const getFileExt = (filename) => {
  return filename.slice(((filename.lastIndexOf('.') - 1) >>> 0) + 2)
}
007 创建独一无二字符串
const createUniqueString = () => {
  const timestamp = +new Date() + ''
  const randomNum = parseInt((1 + Math.random()) * 65536) + ''
  return (+(randomNum + timestamp)).toString(32)
}
008 事件绑定与解绑
/**
 * @description 绑定事件 on(element, event, handler)
 */
const on = (function () {
  if (document.addEventListener) {
    return function (element, event, handler) {
      if (element && event && handler) {
        element.addEventListener(event, handler, false)
      }
    }
  } else {
    return function (element, event, handler) {
      if (element && event && handler) {
        element.attachEvent('on' + event, handler)
      }
    }
  }
})()
​
/**
 * @description 解绑事件 off(element, event, handler)
 */
const off = (function () {
  if (document.removeEventListener) {
    return function (element, event, handler) {
      if (element && event) {
        element.removeEventListener(event, handler, false)
      }
    }
  } else {
    return function (element, event, handler) {
      if (element && event) {
        element.detachEvent('on' + event, handler)
      }
    }
  }
})()
009 获取视频时长
const getVideoDuration = () => {
  const fileObj = this.$refs.file.files[0]
  const video = document.createElement('video')
  video.preload = 'metadata'
  video.onloadedmetadata = () => {
    window.URL.revokeObjectURL(video.src)
    const duration = video.duration
  }
  video.src = URL.createObjectURL(fileObj)
}
010 判断是否重复操作
const isRepeat = (function () {
  const reData = {}
  return function (name = 'default', time = 300) {
    const now = new Date()
    const re = now - (isNaN(reData[name]) ? 0 : reData[name])
    reData[name] = now
    return re <= time
  }
})()
011 Chunk array
长数组按指定长度拆分为嵌套子数组：
const chunk = (arr, size) => Array.from({ length: Math.ceil(arr.length / size) }, (v, i) => arr.slice(size * i, size * i + size))
chunk([1, 2, 3, 4, 5], 2) // [[1, 2], [3, 4], [5]]
012 判断是否为本地开发环境
const isLocalhost = Boolean(
  window.location.hostname === 'localhost' ||
    // [::1] is the IPv6 localhost address.
    window.location.hostname === '[::1]' ||
    // 127.0.0.0/8 are considered localhost for IPv4.
    window.location.hostname.match(/^127(?:\.(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)){3}$/)
)
013 获取路由参数
如果项目有使用 vue-router 的话，最简单的方式是取 this.$route.query。但是有些项目并没有使用 vue-router，这时可以使用 URLSearchParams。
//  url = "https://xxxx.com?a=1&b=2"
const searchParams = new URLSearchParams(window.location.search)
searchParams.has('a') === true // true
searchParams.get('a') === '1' // true
searchParams.getAll('a') // ["1"]
searchParams.append('c', '3') // "a=1&b=2&c=3"
searchParams.toString() // "a=1&b=2&c=3"
searchParams.set('a', '0') // "a=0&b=2&c=3"
searchParams.delete('a') // "b=2&c=3"
由于 URLSearchParams 的兼容性，老旧浏览器兼容可以使用下面代码：
function getQueryString(name) {
  var reg = new RegExp('(^|&)' + name + '=([^&]*)(&|$)', 'i')
  var r = location.search.substr(1).match(reg)
  if (r != null) {
    return decodeURIComponent(r[2])
  }
  return null
}
014 获取路由参数对象
// 方法一：使用 JSON.parse
const getQuery = (url) => {
  const search = url.split('?')[1]
  if (!search) {
    return {}
  }
  return JSON.parse('{"' + decodeURIComponent(search).replace(/"/g, '\\"').replace(/&/g, '","').replace(/=/g, '":"').replace(/\+/g, ' ') + '"}')
}
​
// 方法二：直接遍历
const getQuery = (url) => {
  const obj = {}
  const search = url.split('?')[1]
  if (!search) return obj
  const arr = search.split('&')
  for (item of arr) {
    const keyValue = item.split('=')
    obj[keyValue[0]] = keyValue[1]
  }
  return obj
}
015 构建 FormData 表单
const formBuilder = (obj) => {
  const formData = new FormData()
  Object.keys(obj).forEach((k) => {
    formData.append(k, obj[k])
  })
  return formData
}
016 AES 加解密
const CryptoJS = require('crypto-js')
​
const key = CryptoJS.enc.Utf8.parse('1234123412ABCDEF') // 密钥
const iv = CryptoJS.enc.Utf8.parse('ABCDEF1234123412') // 密钥偏移量
​
/**
 * 消息加密
 * @param {*} msg
 */
export const encodeMsg = (msg) => {
  const msgStr = JSON.stringify(msg)
  const srcs = CryptoJS.enc.Utf8.parse(msgStr)
  const encrypted = CryptoJS.AES.encrypt(srcs, key, {
    iv,
    mode: CryptoJS.mode.CBC,
    padding: CryptoJS.pad.Pkcs7,
  })
  const encryptedStr = encrypted.ciphertext.toString()
  return encryptedStr
}
​
/**
 * 消息解密
 * @param {*} msgStr
 */
export const decodeMsg = (msgStr) => {
  const encryptedHexStr = CryptoJS.enc.Hex.parse(msgStr)
  const srcs = CryptoJS.enc.Base64.stringify(encryptedHexStr)
  const decrypt = CryptoJS.AES.decrypt(srcs, key, {
    iv,
    mode: CryptoJS.mode.CBC,
    padding: CryptoJS.pad.Pkcs7,
  })
  const decryptedStr = decrypt.toString(CryptoJS.enc.Utf8)
  return decryptedStr.toString()
}
017 去除 HTML 标签
正则表达式
export const removeHtmlTag = (raw) => raw.replace(/<[\s\S]+?>/g, '')
DOM API
export const removeHtmlTag = (raw) => {
  const box = document.createElement('template')
  box.innerHTML = raw
  return box.content.textContent
}
018 HTML 转义与反转义
// 转义
let textNode = document.createTextNode('<span>by zhangxinxu</span>')
let div = document.createElement('div')
div.append(textNode)
console.log(div.innerHTML)
// &lt;span&gt;by zhangxinxu&lt;/span&gt;
​
// 反转义
let str = '&lt;span&gt;by zhangxinxu&lt;/span&gt;'
let doc = new DOMParser().parseFromString(str, 'text/html')
console.log(doc.documentElement.textContent)
// <span>by zhangxinxu</span>
019 判断合法日期
export const isDate = (raw) => !isNaN(+new Date(raw))
利用 Date 构造函数内部的算法，对于无法解析为日期的数据，date.toString() 会返回 Invalid Date，date.getTime() 对应的返回值则是 NaN。而算数运算符会调用对象的 valueOf() 方法，date.valueOf() 的返回值又与 date.getTime() 相同。
020 多行文本溢出省略效果
// 单行：
overflow: hidden;
text-overflow: ellipsis;
white-space: nowrap;
​
// 多行：
display: -webkit-box;
-webkit-box-orient: vertical;
-webkit-line-clamp: 3; //行数
overflow: hidden;
021 文件大小单位转换
export const bytesSize = (bytes) => {
  if ((bytes >> 30) & 0x3ff) {
    bytes = (bytes >>> 30) + '.' + String(bytes & (3 * 0x3ff)).substr(0, 2) + 'GB'
  } else if ((bytes >> 20) & 0x3ff) {
    bytes = (bytes >>> 20) + '.' + String(bytes & (2 * 0x3ff)).substr(0, 2) + 'MB'
  } else if ((bytes >> 10) & 0x3ff) {
    bytes = (bytes >>> 10) + '.' + String(bytes & 0x3ff).substr(0, 2) + 'KB'
  } else if ((bytes >> 1) & 0x3ff) bytes = (bytes >>> 1) + 'Bytes'
  else bytes = bytes + 'Byte'
  return bytes
}
022 react ref 计算元素的尺寸
const demo = () => {
  const ref = useCallback((el: HTMLElement | null) => {
    if (el) {
      setTimeout(() => {
        const boundingRect = el.getBoundingClientRect()
        props.onHeight(boundingRect.height)
      })
    }
  }, [])
​
  return <div ref={ref}>react ref 计算元素的尺寸</div>
}
023 react 动态加载 script
useEffect(() => {
  const script = document.createElement('script')
  script.type = 'text/javascript'
  script.src = 'https://utteranc.es/client.js'
  script.async = true
  script.crossOrigin = 'anonymous'
  script.setAttribute('repo', 'chanshiyucx/aurora')
  script.setAttribute('theme', 'github-dark')
  script.setAttribute('issue-term', title)
​
  const dom = document.querySelector('.comment')
  dom?.appendChild(script)
  return () => {
    dom?.removeChild(script)
  }
}, [title])
024 获取图片源文件
<!-- 1. data attribute -->
<img src="img/journey_thumbnail.jpg" data-original="img/journey.jpg" />
​
<!-- 2. anchor link -->
<a href="demo/img/journey.jpg">
  <img src="demo/img/journey_thumbnail.jpg" />
</a>
export function getOriginalSource(el) {
  if (el.dataset.original) {
    return el.dataset.original
  } else if (el.parentNode.tagName === 'A') {
    return el.parentNode.getAttribute('href')
  } else {
    return null
  }
}
最近更新 7mo ago