files.js

"use strict";
var path = require('path');
var fs   = require('fs');

/**
 * Find all files recursively in specific folder with specific extension, e.g:
 * findFilesInDir('./project/src', '.html') ==> ['./project/src/a.html','./project/src/build/index.html']
 * @param  {String} startPath    Path relative to this file or other file which requires this files
 * @param  {String} filter       Extension name, e.g: '.html'
 * @return {Array}               Result files with path string in an array
 */
function findFilesInDir(startPath, filter){

  var results = [];
  var re = new RegExp(`${filter}$`, 'i');

  if(!fs.existsSync(startPath)){
    return;
  }

  var files = fs.readdirSync(startPath);

  for(var i=0 ; i<files.length; i++){
    var filename=path.join(startPath, files[i]);
    var stat = fs.lstatSync(filename);
    if (stat.isDirectory()){
      results = results.concat(findFilesInDir(filename, filter)); //recurse
    }
    else if (re.test(filename)) {
      results.push(filename);
    }
  }
  return results;
}

module.exports = {
  findFilesInDir: findFilesInDir
};