[github地址：https://github.com/ABCDdouyae...]
pad
给字符串的左右加padding,也可以用于删减字符串两端
用法：pad(str, length, options)|pad(length, str, options)
options:
- char (string)： 指定字符填充
- colors (boolean)：Ajust to hidden terminal color characters, you may also use require 'pad/lib/colors' to avoid passing this option.
- strip (boolean)：要求的长度小于原字符串长度，会对原字符串删减，默认false
- fixed_width (boolean)：An optimization option to disable the usage of the wcwdith package to handle the discovery of characters using more than one column for display. one column to display
- wcwidth_options (object)：Options passed to the wcwidth package used to calculate the display width of characters using more than one column.
返回：string