Object相關操做

// 輸入目標, 返回目標具體類型
/**
 * @param {any} target 要判斷類型的目標對象
 * @returns 返回相應類型
 */
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
}

// 檢查目標是否有效( 空數組以及空對象被認爲不合法 )
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
    }
  }
}

// 駝峯與下劃線寫法相互轉換
/**
* @function 駝峯命名->下劃線命名
* @param  {string} name {駝峯名稱}
* @return {string} {下劃線名稱}
*/
export const toLineName = (name) => {
  return name && name.replace(/([A-Z])/g, '_$1').toLowerCase()
}
/**
* @function 下劃線命名->駝峯命名
* @param  {string} name {下劃線名稱}
* @return {string} {駝峯名稱}
*/
export const toHumpName = (name) => {
  return name && name.replace(/_([a-zA-Z])/g, function (all, letter) {
    return letter.toUpperCase()
  })
}

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

// 類數組轉爲真數組
/**
 * 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
}