Read files from inout dir, apply the regex, write all files to output dir all at once - node.js

Question

I have two folders, input and output folder with many text files in the below format. How do I read all the files from the input folder,run the regex and write all the updated files to another output folder?I am using nodejs.
Input: $.Carpool[0].NoofSeats], [$.Carpool[1].NoofSeats]
So after replace with regex the updated text file should be:
Regex: str = str.replace(/\.[A-Z]/g, (m0) => m0.toLowerCase());
Output: [$.carpool[0].noOfSeats], [$.carpool[1].noOfSeats]
So far I got to reading files from the directory:
const fs= require("fs");
let directory = "Input" // Desktop/Input
let files = fs.readdirSync(directory)
console.log(files);

Answer 1

You want to loop through the files, assuming if the contents are a text file in UTF-8 format here is an example.
You use fs.readFile to read a specific file after listing directory.
Then use fs.writeFile to write a new file with contents.
I use /directory/${f} for the new file directory path and ${f} for filename that was opened.
const fs = require("fs");
// Directory
let directory = "/";
// Files
let files = fs.readdirSync(directory);
// Loop through the files
files.forEach(f => {
// Read the contents in UTF-8 format
fs.readFile(f, 'utf8', function(err, contents) {
if (err) { console.log(err); }
// Output Contents
console.log(contents);
// Perform regex here
contents = contents.replace(/\.[A-Z]/g, (m0) => m0.toLowerCase());
// Write new file to path /new, with contents
fs.writeFile(`/directory/${f}`, contents, function(err) {
if (err) {
// Error writing
return console.log(err);
}
console.log("The file was saved!");
});
});
});