why else statement runs even if the if statement being true?

// file manager in node js --- FIRST PROJECT

const fs = require('fs'); //file system module
const path = require('path');

// First - specyfing the files extensions....
const images = ['.png', '.jpg', '.jpeg'];
const document = ['pdf', 'docx', 'doc'];
const videos = ['mp4', 'mov'];

//Read files from the source directory (folder named 'source')

//readdir - get  list of every file inside the folder...
fs.readdir('./source', (err, files) => {
  if (err) {
    console.log(err);
  } else {
    files.forEach((file) => {
      const filesExtention = path.extname(file).toLowerCase(); //path.extname allow you to extract specific components from file paths, such as file extensions.
      if (filesExtention === images[1]) {
        console.log('there is a .jpg file');
      } else {
        console.log('nothing here!');
      }
    });
  }
});