常用的js函数，工具类封装 收集

js_extra_util.js

const extra = {}

// 密码检测密码强度
extra.checkStrength = function (sValue) {
  let modes = 0

  if (sValue.length < 1) return modes

  // 正则表达式验证符合要求的
  if (/\d/.test(sValue)) modes++; //数字

  if (sValue.length > 7) modes++; //长度大于7

  if (/[a-z]/.test(sValue)) modes++; //小写

  if (/[A-Z]/.test(sValue)) modes++; //大写

  if (/\W/.test(sValue)) modes++; //特殊字符

  return modes
}

// 图片预览 file 对象, 预览的img id
extra.previewImage = function (file, img) {
  let preImg = $('#' + img);
  if (file["files"] && file["files"][0]) {
    let reader = new FileReader();
    reader.onload = function (evt) {
      preImg.attr({
        src: evt.target.result
      });
    }
    reader.readAsDataURL(file.files[0]);
  }
}

extra.scaleImage = function (imgElem, FitWidth, FitHeight) {
  let image = new Image();
  image.src = imgElem.src;
  if (image.width > 0 && image.height > 0) {
    if (image.width / image.height >= FitWidth / FitHeight) {
      if (image.width > FitWidth) {
        imgElem.width = FitWidth;
        imgElem.height = (image.height * FitWidth) / image.width;
      } else {
        imgElem.width = image.width;
        imgElem.height = image.height;
      }
    } else {
      if (image.height > FitHeight) {
        imgElem.height = FitHeight;
        imgElem.width = (image.width * FitHeight) / image.height;
      } else {
        imgElem.width = image.width;
        imgElem.height = image.height;
      }
    }
  }
}

// ajax 上传文件
extra.ajaxUpload = function (url, input, opts) {
  let elem = typeof input === 'string' ? $(input) : input

  // no file to upload
  if (!elem[0].files[0]) {
    return
  }

  opts = this.extend({
    data: {},
    onSuccess: null,
    onError: null
  }, opts)

  let formData = new FormData()

  formData.append("file", elem[0].files[0])

  // 追加数据
  for (let key in opts.data) {
    formData.append(key, opts.data[key])
  }

  $.ajax({
    url: url,
    type: 'POST',
    data: formData,
    // 告诉jQuery不要去处理发送的数据

    processData: false,
    // 告诉jQuery不要去设置Content-Type请求头

    contentType: false,
    beforeSend: function () {
      console.log("正在进行，请稍候... ...")
    },
    success: opts.onSuccess,
    error: opts.onError
  })
}

/**
 * 回到顶部
 * @param {string} wrapper
 * @param {string} icon
 */
extra.backTop = function (wrapper, icon) {
  let slideToTop = $("<div></div>")

  slideToTop.html(icon ? icon : '<i class="fa fa-chevron-up"></i>')
  slideToTop.css({
    position: 'fixed',
    bottom: '20px',
    right: '25px',
    width: '40px',
    height: '40px',
    color: '#eee',
    'font-size': '',
    'line-height': '40px',
    'text-align': 'center',
    'background-color': '#222d32',
    cursor: 'pointer',
    'border-radius': '5px',
    'z-index': '99999',
    opacity: '.7',
    'display': 'none'
  })

  slideToTop.on('mouseenter', function () {
    $(this).css('opacity', '1')
  })

  slideToTop.on('mouseout', function () {
    $(this).css('opacity', '.7')
  })

  $(wrapper).append(slideToTop)

  $(window).scroll(function () {
    if ($(window).scrollTop() >= 150) {
      if (!$(slideToTop).is(':visible')) {
        $(slideToTop).fadeIn(500);
      }
    } else {
      $(slideToTop).fadeOut(500);
    }
  })

  $(slideToTop).click(function () {
    $("body").animate({
      scrollTop: 0
    }, 500);
  })
}

js_util.js

/************************************************
 * helper functions
 ************************************************
 */
function noop() {
}

function is_undefined(obj) {
  return typeof obj === 'undefined'
}

function is_null(obj) {
  return obj === null
}

function is_function(item) {
  if (typeof item === 'function') {
    return true
  }

  let type = Object.prototype.toString(item)

  return type === '[object Function]' || type === '[object GeneratorFunction]'
}

function is_string(obj) {
  return typeof obj === 'string'
}

function is_array(obj) {
  return Array.isArray(obj) || obj instanceof Array
}

function is_object(obj) {
  return toString.call(obj) === '[object Object]'
}

function is_empty_object(obj) {
  if (typeof obj !== 'object') {
    return true;
  }

  return Object.keys(obj).length === 0;
}

// 检测是不是扁平对象 (使用 “{}” 或 “new Object” 创建).
function is_plain_object(obj) {
  if (typeof (obj) !== 'object' || obj.nodeType || obj !== null && obj !== undefined && obj === obj.window) {
    return false
  }

  return !(obj.constructor && !Object.prototype.hasOwnProperty.call(obj.constructor.prototype, 'isPrototypeOf'))
}

function in_array (arr, item) {
  return arr.indexOf(item) > -1
}

function is_numeric(value) {
  let type = typeof value;

  return (type === 'number' || type === 'string') && !Number.isNaN(value - Number.parseFloat(value));
}

function json_encode(obj) {
  return JSON.stringify(obj)
}

function json_decode(str) {
  return JSON.parse(str)
}

/************************************************
 * helper
 ************************************************
 */
const toString = Object.prototype.toString
const EmptyArray = []

const util = {
  // helper method
  isUndefined: is_undefined,
  isNull: is_null,
  isFunction: is_function,
  isString: is_string,
  isArray: is_array,
  isObject: is_object,
  isNumeric: is_numeric,

  // number
  toFixed(num, decimals) {
    decimals = decimals || 2

    return (num * 1).toFixed(decimals)
  },

  // string
  lcFirst (str) {
    return str.substr(0, 1).toLowerCase() + str.slice(1)
  },
  ucFirst (str) {
    return str.substr(0, 1).toUpperCase() + str.slice(1)
  },
  trim (str){
    return str.replace(/(^\s*)|(\s*$)/g, "");
  },
  ltrim (str) {
    return str.replace(/(^\s*)/g, "");
  },
  rtrim () {
    return this.replace(/(\s*$)/g, "");
  },

  // object
  isEmptyObject: is_empty_object,

  // array
  inArray: in_array,
  arrayIfy(obj, start, end) {
    return EmptyArray.slice.call(obj, start, end)
  },

  // 合并2个对象的内容
  extend(dst, src) {
    if (Object.assign) {
      return Object.assign({}, dst, src)
    }

    for (let key in src) {
      if (src.hasOwnProperty(key))
        dst[key] = src[key]
    }

    return dst
  },
  // 合并多个对象的内容到第一个对象。
  extend2(out) {
    out = out || {}

    for (let i = 1; i < arguments.length; i++) {
      if (!arguments[i])
        continue

      for (let key in arguments[i]) {
        if (arguments[i].hasOwnProperty(key))
          out[key] = arguments[i][key]
      }
    }

    return out
  },
  // 合并第二个数组内容到第一个数组
  merge(...args) {
    return [].concat(...args)
  },
  clone(src) {
    return extend({}, src)
  },

  // json
  jsonEncode(obj) {
    return json_encode(obj)
  },
  jsonDecode(str) {
    return json_decode(str)
  },
  toJson (_form) {
    // to json object
    return JSON.parse(JSON.stringify(_form))
  },

  // other
  bindLeaveTips () {
    window.beforeunload = function () {
      return '您输入的内容尚未保存，确定离开此页面吗？'
    }
  },
  unbindLeaveTips () {
    window.onbeforeunload = null
  }
}