JavaScript utils 代码

js 常见正则

https://github.com/cdoco/common-regex

'1231231.4314'.replace(/\B(?=(\d{3})+(?!\d))/g, ',')
会切割小数点后
'1231231.4314'.replace(/(?<!\.\d*)\B(?=(\d{3})+(?!\d))/g, ",")


px 转成 vw

"  margin: 42px 15px 15px 15px;".replace(/(\s)(?=\d*px)/g, ' \(').replace(/px/g, 'vw\/3.75\)')

node 文件递归改名

const fs = require('fs')
const path = require('path')

const changeName = (old, removeStirng) => {
  const index = old.indexOf(removeStirng)
  if (index > 0) {
    const suffix = old.slice(old.lastIndexOf('.'))
    const newName = old.slice(0, index) + suffix
    fs.rename(old, newName, function(err) {
      if ( err ) console.log('changeName ERROR: ' + err);
    })
  }
}

function isFile(dir) {
  return fs.statSync(dir).isFile()
}

const getNames = dir => {
  return new Promise((res, rej) => {
    fs.readdir(dir, (err, files) => {
      if (err) {
        rej(err)
      } else {
        const names = files.map(i => path.join(dir, i))
        res(names)
      }
    })
  })
}

const parseDir = () => {
  const args = process.argv.slice(2)
  return [args[0], args[1]]
}

const changeNameAll = (dir, removeStirng) => {
  getNames(dir)
    .then(names => {
      names.forEach(item => {
        if (isFile(item)) {
          changeName(item, removeStirng)
        } else {
          changeNameAll(item, removeStirng)
        }
      })
    })
    .catch(err => {
      console.log('getNames err: ', err)
    })
}

const main = () => {
  const [dir, removeStirng] = parseDir()
  changeNameAll(dir, removeStirng)
}

// 批量改名软件，args 绝对路径 去除特殊字符串
main()

sha1

function encodeUTF8(s) {
  var i, r = [], c, x;
  for (i = 0; i < s.length; i++)
    if ((c = s.charCodeAt(i)) < 0x80) r.push(c);
    else if (c < 0x800) r.push(0xC0 + (c >> 6 & 0x1F), 0x80 + (c & 0x3F));
    else {
      if ((x = c ^ 0xD800) >> 10 == 0) //对四字节UTF-16转换为Unicode
        c = (x << 10) + (s.charCodeAt(++i) ^ 0xDC00) + 0x10000,
          r.push(0xF0 + (c >> 18 & 0x7), 0x80 + (c >> 12 & 0x3F));
      else r.push(0xE0 + (c >> 12 & 0xF));
      r.push(0x80 + (c >> 6 & 0x3F), 0x80 + (c & 0x3F));
    };
  return r;
};

function sha1(s) {
  var data = new Uint8Array(encodeUTF8(s))
  var i, j, t;
  var l = ((data.length + 8) >>> 6 << 4) + 16, s = new Uint8Array(l << 2);
  s.set(new Uint8Array(data.buffer)), s = new Uint32Array(s.buffer);
  for (t = new DataView(s.buffer), i = 0; i < l; i++)s[i] = t.getUint32(i << 2);
  s[data.length >> 2] |= 0x80 << (24 - (data.length & 3) * 8);
  s[l - 1] = data.length << 3;
  var w = [], f = [
    function () { return m[1] & m[2] | ~m[1] & m[3]; },
    function () { return m[1] ^ m[2] ^ m[3]; },
    function () { return m[1] & m[2] | m[1] & m[3] | m[2] & m[3]; },
    function () { return m[1] ^ m[2] ^ m[3]; }
  ], rol = function (n, c) { return n << c | n >>> (32 - c); },
    k = [1518500249, 1859775393, -1894007588, -899497514],
    m = [1732584193, -271733879, null, null, -1009589776];
  m[2] = ~m[0], m[3] = ~m[1];
  for (i = 0; i < s.length; i += 16) {
    var o = m.slice(0);
    for (j = 0; j < 80; j++)
      w[j] = j < 16 ? s[i + j] : rol(w[j - 3] ^ w[j - 8] ^ w[j - 14] ^ w[j - 16], 1),
        t = rol(m[0], 5) + f[j / 20 | 0]() + m[4] + w[j] + k[j / 20 | 0] | 0,
        m[1] = rol(m[1], 30), m.pop(), m.unshift(t);
    for (j = 0; j < 5; j++)m[j] = m[j] + o[j] | 0;
  };
  t = new DataView(new Uint32Array(m).buffer);
  for (var i = 0; i < 5; i++)m[i] = t.getUint32(i << 2);

  var hex = Array.prototype.map.call(new Uint8Array(new Uint32Array(m).buffer), function (e) {
    return (e < 16 ? "0" : "") + e.toString(16);
  }).join("");

  return hex;
};

压缩图片上传

function compress(img) {
  // 图片压缩
  var canvas = document.createElement('canvas')
  var ctx = canvas.getContext('2d')
  //    瓦片canvas
  var tCanvas = document.createElement('canvas')
  var tctx = tCanvas.getContext('2d')

  var width = img.width
  var height = img.height
  // 如果图片大于四百万像素，计算压缩比并将大小压至400万以下
  var ratio
  if ((ratio = (width * height) / 4000000) > 1) {
    ratio = Math.sqrt(ratio)
    width /= ratio
    height /= ratio
  } else {
    ratio = 1
  }
  canvas.width = width
  canvas.height = height
  //        铺底色
  ctx.fillStyle = '#fff'
  ctx.fillRect(0, 0, canvas.width, canvas.height)
  // 如果图片像素大于100万则使用瓦片绘制
  var count
  if ((count = (width * height) / 1000000) > 1) {
    count = ~~(Math.sqrt(count) + 1) // 计算要分成多少块瓦片
    //            计算每块瓦片的宽和高
    var nw = ~~(width / count)
    var nh = ~~(height / count)
    tCanvas.width = nw
    tCanvas.height = nh
    for (var i = 0; i < count; i++) {
      for (var j = 0; j < count; j++) {
        tctx.drawImage(img, i * nw * ratio, j * nh * ratio, nw * ratio, nh * ratio, 0, 0, nw, nh)
        ctx.drawImage(tCanvas, i * nw, j * nh, nw, nh)
      }
    }
  } else {
    ctx.drawImage(img, 0, 0, width, height)
  }
  // 进行最小压缩
  var ndata = canvas.toDataURL('image/jpeg', 0.8)
  // console.log('压缩前：' + initSize);
  // console.log('压缩后：' + ndata.length);
  // console.log('压缩率：' + ~~(100 * (initSize - ndata.length) / initSize) + "%");
  tCanvas.width = tCanvas.height = canvas.width = canvas.height = 0
  return ndata
}

function getBlob(buffer, format) {
  try {
    return new Blob(buffer, { type: format })
  } catch (e) {
    var bb = new (window.BlobBuilder ||
      window.WebKitBlobBuilder ||
      window.MSBlobBuilder)()
    buffer.forEach(function(buf) {
      bb.append(buf)
    })
    return bb.getBlob(format)
  }
}

function upimg(db) {
  return new Promise((resolve, reject) => {
    var img = new Image()
    img.onload = () => {
      db.content.length
      var base64 = compress(img)
      if (base64.length / db.content.length < 0.02) {
        return reject('请控制上传图片大小')
      }
      var text = window.atob(base64.split(',')[1])
      var buffer = new Uint8Array(text.length)
      for (var i = 0; i < text.length; i++) {
        buffer[i] = text.charCodeAt(i)
      }
      var blob = getBlob([buffer], db.file.type)
      resolve(blob)
    }
    img.src = db.content
  })
}

实用代码

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封装 ajax

function ajax(method, url, data, reseponseCallback) {
  var r = new XMLHttpRequest()
  // 设置请求方法和请求地址
  r.open(method, url, true)
  // 设置发送的数据的格式
  r.setRequestHeader('Content-Type', 'application/json')
  // 注册响应函数
  r.onreadystatechange = function() {
    if (r.readyState === 4) {
      // console.log('ready state == 4')
      var data = JSON.parse(r.response)
      // console.log('ready state. data', data)
      reseponseCallback(data)
    }
    // console.log('on state change', r)
  }
  // 发送请求
  data = JSON.stringify(data)
  r.send(data)
}

时间格式化

function timeFormat(timestamp) {
  const format = (data) => data > 10 ? data : '0' + data
  const time = new Date(timestamp)
  const year = time.getFullYear()
  let month = time.getMonth() + 1
  month = format(month)
  let day = time.getDate()
  day = format(day)
  let hour = time.getHours()
  hour = format(hour)
  let minute = time.getMinutes()
  minute = format(minute)
  let second = time.getSeconds()
  second = format(second)
  
  return `${year}-${month}-${day} ${hour}:${minute}:${second}`
}