前端函数封装

解析URL参数

/*
 * 参数: 
*   url: [String] 解析的URL，可选，不传该值默认本地href
* 返回：
*   obj：[Object] 参数集合对象
 */

function getQueryParam(url) {
    const href = url || window.location.href;
    let args = href.split('?');
    
    // 没有参数直接返回{}
    if (args[0] === href) {
        return {};
    }
    
    var hrefarr = args[1].split('#')[0].split('&');
    var obj = {};
    for (var i = 0; i < hrefarr.length; i++) {
        hrefarr[i] = hrefarr[i].split('=');
        obj[hrefarr[i][0]] = hrefarr[i][1];
    }
    return obj;
}

解析身份证号码信息

/* 参数: 
*   IdCard: [String] 身份证号码
*   type: [Number] 1/2/3 
* 返回：
*   type：1 => birthday [String] 出生日期
*   type：2 => sex [Number] 性别
*   type：3 => age [Number] 年龄
*/
formatIdCard (IdCard, type) {
  if (type === 1) {
    // 获取出生日期
    var birthday = IdCard.substring(6, 10) + '-' + IdCard.substring(10, 12) '-' + IdCard.substring(12, 14)
    return birthday
  }
  if (type === 2) {
    // 获取性别
    if (parseInt(IdCard.substr(16, 1)) % 2 === 1) {
      return '1' // 男
    } else {
      return '2' // 女
    }
  }
  if (type === 3) {
    // 获取年龄
    var ageDate = new Date()
    var month = ageDate.getMonth() + 1
    var day = ageDate.getDate()
    var age = ageDate.getFullYear() - IdCard.substring(6, 10) - 1
    if (IdCard.substring(10, 12) < month || IdCard.substring(10, 12) === mont&& IdCard.substring(12, 14) <= day) {
      age++
    }
    if (age <= 0) {
      age = 1
    }
    return age
  }
}

获取图片base64

/* 参数:
*   file {file object} 文件对象
* 返回:
*   {Promise}
*/
async function imgToBase64 (file) {
  return new Promise((resolve,reject) => {
    const reader = new FileReader()
    reader.readAsDataURL(file)
    reader.onload = e => {
      resolve(e.target.result)
    }
    reader.onerror = err => {
        reject(err)
    }
  })
}

base64解码

/* base64解码
* 优化中文乱码问题
* @param {String} b64Str 待解码的base64数据
* @returns {string}
*/
function b64ToUtf8(b64Str) {
  return decodeURIComponent(window.atob(b64Str).split('').map(c => '%' + ('00' + c.charCodeAt(0).toString(16)).slice(-2)).join(''))
}

// atob()解码不支持中文
// base64编码前先对中文URL转码
window.btoa(encodeURIComponent(str))

格式化日期

/* 参数: 
*   date: 时间戳 [Date]
*   isTime: 是否返回具体时间 [Boolean]
*   separator: 年月日分隔符 [String]
* 返回：
*   isTime: false => yyyy-MM-dd [String]
*   isTime: true => yyyy-MM-dd HH:mm:ss [String]
*/

const formatDate = (date, isTime = false, separator = '-') => {
  const year = date.getFullYear()
  const month = date.getMonth() + 1
  const day = date.getDate()
  let d = [year, month, day].map(_formatNumber).join(separator)
  if (isTime) {
    const hour = date.getHours()
    const minute = date.getMinutes()
    const second = date.getSeconds()
    const time = [hour, minute, second].map(_formatNumber).join(':')

    d = `${d} ${time}`
  }
  return d
}
const _formatNumber = n => {
  n = n.toString()
  return n[1] ? n : '0' + n
}

// padStart()补齐日期位数
formatDate() {
  const date = new Date()
  const year = date.getFullYear().toString().padStart(4, '0')
  const month = (date.getMonth() + 1).toString().padStart(2, '0')
  const day = date.getDate().toString().padStart(2, '0')
  const result = `${year}-${month}-${day}`
  return result
}

获取某日期若干个工作日后的日期

/* 参数: 
*   time: [String] 给定日期 yyyy-MM-dd
*   itervalByDay: [Number] 相隔工作日
*   separator: [String] 年月日分隔符
* 返回：
*   rq：[String] 匹配的日期yyyy-MM-dd
*/
var getworkday = function(time, itervalByDay, separator = '-'){
  var str = time.split("-");
  
  var date = getDate();
  date.setUTCFullYear(str[0], str[1] - 1, str[2]);
  date.setUTCHours(0, 0, 0, 0);
  
  var millisceonds =date.getTime();
  for(var i = 1; i <= itervalByDay; i++){
    millisceonds += 24 * 60 * 60 * 1000;
    date.setTime(millisceonds);
    // 如果是周末，计数i回退1，既跳过
    if(date.getDay() == 0 || date.getDay() == 6) i--;
  }
  
  var year = date.getFullYear();
  var month = (date.getMonth() + 1);
  var day = date.getDate();
  var rq = year + separator + month + separator + day;
  
  return rq;
}

图片压缩

/* 原理: 把图片宽度、高度调小
* @param file {file object | file base64}
* @param {width, height}：压缩图片宽高
* @returns {Promise}
* 
* Tip： 与imgToBase64()配合使用效果更佳
*/
async function imgToCompressed (file, {
  width,
  height
}) {
  if (typeof file === 'object') {
    file = await imgToBase64(file)
  }

  return new Promise(resolve => {
    var image = new Image()
    image.src = file

    image.onload = () => {
      const _width = image.width
      const _height = image.height
      const canvas = document.createElement('canvas')
      const context = canvas.getContext('2d')
      let data = ''
      if (width && width > _width) {
        width = _width
        height = _height
      } else {
        // 等比例缩放
        width = width || Math.floor(_width * height / _height)
        height = height || Math.floor(width * _height / _width)
      }

      canvas.width = width
      canvas.height = height

      context.drawImage(image, 0, 0, width, height)
      data = canvas.toDataURL('image/jpeg').replace('data:image/jpeg;base64,', '')

      resolve(data)
    }
  })
}