How do I change file extension with javascript?

filePathReplace.js

// https://stackoverflow.com/a/47949440/1366033
function changeExt(fileName, newExt) {
  var pos = fileName.includes(".") ? fileName.lastIndexOf(".") : fileName.length
  var fileRoot = fileName.substr(0, pos)
  var output = `${fileRoot}.${newExt}`
  return output
}


console.log(changeExt("img.jpeg", "jpg"))             // img.jpg
console.log(changeExt("img.name.jpeg", "jpg"))        // img.name.jpg
console.log(changeExt("host", "csv"))                 // host.csv
console.log(changeExt(".graphqlrc", "graphqlconfig")) // .graphqlconfig

please let me know, how to change extension of a file into simple txt format when we paste it from another folder, for example we have payments.pdf in finance folder, when we paste it into budget folder (another folder), then its extension must be changed into payments.txt

Hey Lakhan, sounds like you'd have to tap into the OS in order to handle copy /paste folder operations. This solution is really just targeted at change the string of a file. You could leverage that in a node job, but there's a lot of other work involved - you might want to ask about it on stack overflow if you can give a clear example of what you're looking to accomplish and what you've tried.