获取文件后缀名

  1. const getExt = (filename) => {
  2.   if (typeof filename == 'string') {
  3.     return filename.split('.').pop().toLowerCase()
  4.   } else {
  5.     throw new Error('filename must be a string type')
  6.   }
  7. }

生成随机字符串

  1. const uuid = (length, chars) => {
  2.   chars =
  3.     chars ||
  4.     '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
  5.   length = length || 8
  7.   let result = ''
  8.   for (let i = length; i > 0; --i) {
  9.     result +=
  10.       // chars[Math.floor(Math.random() * chars.length)]
  11.       chars[(Math.random() * chars.length) | 0]
  12.   }
  13.   return result
  14. }

image.png

保留小数点后n位

  1. const cutNumber = (num, no) => {
  2.   if (typeof num != 'number') {
  3.     num = Number(num)
  4.   }
  5.   return Number(num.toFixed(no))
  6. }
  7. const a = 38 / 3
  8. console.log(cutNumber(a, 2))//12.67