$3

Define a pattern:

To define a pattern just add "(?var)" on the section of the pattern where the pad should apply on it.

How to use it:

``
const stringPadder = require("string-pad-pattern");

const testString = "file-1.js"
,pattern = "file-(?var).js" //string pattern for example "salary_(?var)_group_a"
,padLength = 5 //expected lengh of the paded region specified in the pattern
,padString = '0' //character or characters to pad the string
,padRight = false; //apply padding to the right, defualt to false

let result = stringPadder.padPattern(testString, pattern, padLength, padString);

console.log(result);
//output file-00001.js

`

Test

`
npm test

``