5. 20 个 JS 工具函数助力高效开发

前言

日常开发中，面对各种不同的需求，我们经常会用到以前开发过的一些工具函数，把这些工具函数收集起来，将大大提高我们的开发效率。

1、校验数据类型

export const typeOf = function(obj) {
  return Object.prototype.toString.call(obj).slice(8, -1).toLowerCase()
}

示例：

typeOf('树哥')  // string
typeOf([])  // array
typeOf(new Date())  // date
typeOf(null) // null
typeOf(true) // boolean
typeOf(() => { }) // function

2、防抖

export const debounce = (() => {
  let timer = null
  return (callback, wait = 800) => {
    timer&&clearTimeout(timer)
    timer = setTimeout(callback, wait)
  }
})()

如 vue 中使用

methods: {
  loadList() {
    debounce(() => {
      console.log('加载数据')
    }, 500)
  }
}

3、节流

export const throttle = (() => {
  let last = 0
  return (callback, wait = 800) => {
    let now = +new Date()
    if (now - last > wait) {
      callback()
      last = now
    }
  }
})()

4、手机号脱敏

export const hideMobile = (mobile) => {
  return mobile.replace(/^(\d{3})\d{4}(\d{4})$/, "$1****$2")
}

5、开启全屏

export const launchFullscreen = (element) => {
  if (element.requestFullscreen) {
    element.requestFullscreen()
  } else if (element.mozRequestFullScreen) {
    element.mozRequestFullScreen()
  } else if (element.msRequestFullscreen) {
    element.msRequestFullscreen()
  } else if (element.webkitRequestFullscreen) {
    element.webkitRequestFullScreen()
  }
}

6、关闭全屏

export const exitFullscreen = () => {
  if (document.exitFullscreen) {
    document.exitFullscreen()
  } else if (document.msExitFullscreen) {
    document.msExitFullscreen()
  } else if (document.mozCancelFullScreen) {
    document.mozCancelFullScreen()
  } else if (document.webkitExitFullscreen) {
    document.webkitExitFullscreen()
  }
}

7、大小写转换

参数：

• str 待转换的字符串

• type 1-全大写 2-全小写 3-首字母大写

  export const turnCase = (str, type) => {
  switch (type) {
    case 1:
      return str.toUpperCase()
    case 2:
      return str.toLowerCase()
    case 3:
      //return str[0].toUpperCase() + str.substr(1).toLowerCase() // substr 已不推荐使用
      return str[0].toUpperCase() + str.substring(1).toLowerCase()
    default:
      return str
  }
  }

  示例：

  turnCase('vue', 1) // VUE
  turnCase('REACT', 2) // react
  turnCase('vue', 3) // Vue

  8、解析URL参数

  export const getSearchParams = () => {
  const searchPar = new URLSearchParams(window.location.search)
  const paramsObj = {}
  for (const [key, value] of searchPar.entries()) {
    paramsObj[key] = value
  }
  return paramsObj
  }

  示例：
  // 假设目前位于 https://****com/index?id=154513&age=18;
  getSearchParams(); // {id: “154513”, age: “18”}

  9、判断手机是Andoird还是IOS

  /** 
  * 1: ios
  * 2: android
  * 3: 其它
  */
  export const getOSType=() => {
  let u = navigator.userAgent, app = navigator.appVersion;
  let isAndroid = u.indexOf('Android') > -1 || u.indexOf('Linux') > -1;
  let isIOS = !!u.match(/\(i[^;]+;( U;)? CPU.+Mac OS X/);
  if (isIOS) {
    return 1;
  }
  if (isAndroid) {
    return 2;
  }
  return 3;
  }

  10、数组对象根据字段去重

  参数：

• arr 要去重的数组

• key 根据去重的字段名

  export const uniqueArrayObject = (arr = [], key = 'id') => {
  if (arr.length === 0) return
  let list = []
  const map = {}
  arr.forEach((item) => {
    if (!map[item[key]]) {
      map[item[key]] = item
    }
  })
  list = Object.values(map)
  return list
  }

  示例： ``` const responseList = [ { id: 1, name: ‘树哥’ }, { id: 2, name: ‘黄老爷’ }, { id: 3, name: ‘张麻子’ }, { id: 1, name: ‘黄老爷’ }, { id: 2, name: ‘张麻子’ }, { id: 3, name: ‘树哥’ }, { id: 1, name: ‘树哥’ }, { id: 2, name: ‘黄老爷’ }, { id: 3, name: ‘张麻子’ }, ]

uniqueArrayObject(responseList, ‘id’) // [{ id: 1, name: ‘树哥’ },{ id: 2, name: ‘黄老爷’ },{ id: 3, name: ‘张麻子’ }]

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## 11、滚动到页面顶部

export const scrollToTop = () => { const height = document.documentElement.scrollTop || document.body.scrollTop; if (height > 0) { window.requestAnimationFrame(scrollToTop); window.scrollTo(0, height - height / 8); } }

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## 12、滚动到元素位置

export const smoothScroll = element =>{ document.querySelector(element).scrollIntoView({ behavior: ‘smooth’ }); };

**示例：**

smoothScroll(‘#target’); // 平滑滚动到 ID 为 target 的元素

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## 13、uuid

export const uuid = () => { const temp_url = URL.createObjectURL(new Blob()) const uuid = temp_url.toString() URL.revokeObjectURL(temp_url) //释放这个url return uuid.substring(uuid.lastIndexOf(‘/‘) + 1) }

**示例：**<br />uuid() _// a640be34-689f-4b98-be77-e3972f9bffdd_<br />复制代码
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## 14、金额格式化
**参数：**
- **{number} number：要格式化的数字**
- **{number} decimals：保留几位小数**
- **{string} dec_point：小数点符号**
- **{string} thousands_sep：千分位符号**

export const moneyFormat = (number, decimals, dec_point, thousands_sep) => { number = (number + ‘’).replace(/[^0-9+-Ee.]/g, ‘’) const n = !isFinite(+number) ? 0 : +number const prec = !isFinite(+decimals) ? 2 : Math.abs(decimals) const sep = typeof thousands_sep === ‘undefined’ ? ‘,’ : thousands_sep const dec = typeof dec_point === ‘undefined’ ? ‘.’ : dec_point let s = ‘’ const toFixedFix = function(n, prec) { const k = Math.pow(10, prec) return ‘’ + Math.ceil(n * k) / k } s = (prec ? toFixedFix(n, prec) : ‘’ + Math.round(n)).split(‘.’) const re = /(-?\d+)(\d{3})/ while (re.test(s[0])) { s[0] = s[0].replace(re, ‘$1’ + sep + ‘$2’) }

if ((s[1] || ‘’).length < prec) { s[1] = s[1] || ‘’ s[1] += new Array(prec - s[1].length + 1).join(‘0’) } return s.join(dec) }

**示例：**

moneyFormat(10000000) // 10,000,000.00 moneyFormat(10000000, 3, ‘.’, ‘-‘) // 10-000-000.000

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## 15、存储操作

class MyCache { constructor(isLocal = true) { this.storage = isLocal ? localStorage : sessionStorage }

setItem(key, value) { if (typeof (value) === ‘object’) value = JSON.stringify(value) this.storage.setItem(key, value) }

getItem(key) { try { return JSON.parse(this.storage.getItem(key)) } catch (err) { return this.storage.getItem(key) } }

removeItem(key) { this.storage.removeItem(key) }

clear() { this.storage.clear() }

key(index) { return this.storage.key(index) }

length() { return this.storage.length } }

const localCache = new MyCache() const sessionCache = new MyCache(false)

export { localCache, sessionCache }

**示例：**

localCache.getItem(‘user’) sessionCache.setItem(‘name’,’树哥’) sessionCache.getItem(‘token’) localCache.clear()

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## 16、下载文件
**参数：**
- **api 接口**
- **params 请求参数**
- **fileName 文件名**

const downloadFile = (api, params, fileName, type = ‘get’) => { axios({ method: type, url: api, responseType: ‘blob’, params: params }).then((res) => { let str = res.headers[‘content-disposition’] if (!res || !str) { return } let suffix = ‘’ // 截取文件名和文件类型 if (str.lastIndexOf(‘.’)) { fileName ? ‘’ : fileName = decodeURI(str.substring(str.indexOf(‘=’) + 1, str.lastIndexOf(‘.’))) suffix = str.substring(str.lastIndexOf(‘.’), str.length) } // 如果支持微软的文件下载方式(ie10+浏览器) if (window.navigator.msSaveBlob) { try { const blobObject = new Blob([res.data]); window.navigator.msSaveBlob(blobObject, fileName + suffix); } catch (e) { console.log(e); } } else { // 其他浏览器 let url = window.URL.createObjectURL(res.data) let link = document.createElement(‘a’) link.style.display = ‘none’ link.href = url link.setAttribute(‘download’, fileName + suffix) document.body.appendChild(link) link.click() document.body.removeChild(link) window.URL.revokeObjectURL(link.href); } }).catch((err) => { console.log(err.message); }) }`

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## 17、时间操作
关于时间操作，没必要自己再写一大串代码了，强烈推荐使用 **day.js[2]**<br />Day.js 是一个仅 2kb 大小的轻量级 JavaScript 时间日期处理库，下载、解析和执行的JavaScript更少，为代码留下更多的时间。
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## 18、深拷贝
**如果确实想要完备的深拷贝，推荐使用 lodash 中的 cloneDeep 方法。**
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## 19、模糊搜索
**参数：**
- **list 原数组**
- **keyWord 查询的关键词**
- **attribute 数组需要检索属性**

export const fuzzyQuery = (list, keyWord, attribute = ‘name’) => { const reg = new RegExp(keyWord) const arr = [] for (let i = 0; i < list.length; i++) { if (reg.test(list[i][attribute])) { arr.push(list[i]) } } return arr }

**示例：**

const list = [ { id: 1, name: ‘树哥’ }, { id: 2, name: ‘黄老爷’ }, { id: 3, name: ‘张麻子’ }, { id: 4, name: ‘汤师爷’ }, { id: 5, name: ‘胡万’ }, { id: 6, name: ‘花姐’ }, { id: 7, name: ‘小梅’ } ] fuzzyQuery(list, ‘树’, ‘name’) // [{id: 1, name: ‘树哥’}]

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## 20、遍历树节点

export const foreachTree = (data, callback, childrenName = ‘children’) => { for (let i = 0; i < data.length; i++) { callback(data[i]) if (data[i][childrenName] && data[i][childrenName].length > 0) { foreachTree(data[i][childrenName], callback, childrenName) } } }

**示例：**<br />假设我们要从树状结构数据中查找 id 为 9 的节点

const treeData = [{ id: 1, label: ‘一级 1’, children: [{ id: 4, label: ‘二级 1-1’, children: [{ id: 9, label: ‘三级 1-1-1’ }, { id: 10, label: ‘三级 1-1-2’ }] }] }, { id: 2, label: ‘一级 2’, children: [{ id: 5, label: ‘二级 2-1’ }, { id: 6, label: ‘二级 2-2’ }] }, { id: 3, label: ‘一级 3’, children: [{ id: 7, label: ‘二级 3-1’ }, { id: 8, label: ‘二级 3-2’ }] }],

let result foreachTree(data, (item) => { if (item.id === 9) { result = item } }) console.log(‘result’, result) // {id: 9,label: “三级 1-1-1”}
```