Object相关操做

// 输入目标, 返回目标具体类型
/**
 * @param {any} target 要判断类型的目标对象
 * @returns 返回相应类型
 */
export const targetType = (target) => {
  let result = ''
  switch (Object.prototype.toString.call(target)) {
    case '[object Object]':
      result = 'Object'
      break
    case '[object Array]':
      result = 'Array'
      break
    case '[object String]':
      result = 'String'
      break
    case '[object Number]':
      result = 'Number'
      break
    case '[object Boolean]':
      result = 'Boolean'
      break
    case '[object Function]':
      result = 'Function'
      break
    case '[object Null]':
      result = 'Null'
      break
    case '[object Undefined]':
      result = 'Undefined'
      break
  }
  return result
}

// 检查目标是否有效( 空数组以及空对象被认为不合法 )
export const checkIsValid = (item) => {
  switch (typeof (item)) {
    case 'undefined': return false
    case 'null': return false
    case 'number': {
      if (isNaN(item)) {
        return false
      } else {
        return true
      }
    }
    case 'object': {
      for (let key in item) {
        return true
      }
      return false
    }
  }
}

// 驼峰与下划线写法相互转换
/**
* @function 驼峰命名->下划线命名
* @param  {string} name {驼峰名称}
* @return {string} {下划线名称}
*/
export const toLineName = (name) => {
  return name && name.replace(/([A-Z])/g, '_$1').toLowerCase()
}
/**
* @function 下划线命名->驼峰命名
* @param  {string} name {下划线名称}
* @return {string} {驼峰名称}
*/
export const toHumpName = (name) => {
  return name && name.replace(/_([a-zA-Z])/g, function (all, letter) {
    return letter.toUpperCase()
  })
}

// 合并对象
/**
 * Mix properties into target object.
 */
export function extend (to, _from) {
  for (const key in _from) {
    to[key] = _from[key]
  }
  return to
}

// 类数组转为真数组
/**
 * Convert an Array-like object to a real Array.
 */
export function toArray (list, start) {
  start = start || 0
  let i = list.length - start
  const ret = new Array(i)
  while (i--) {
    ret[i] = list[i + start]
  }
  return ret
}