How to Increment the Filename If File Already Exists

How to increment the filename if file already exists in javascript

You can check this.state.Files before. A recursive function could be used here. Imagine you load a file named export.csv. The second one would export.csv transformed in export_1.csv. But on a third one named export.csv, the verification would be done on export, leading to export_1 => Error !
The best is to do :

const checkNameOfTheFile = (newFileName) => {
    // Ex 'export.csv'
    const counter = this.state.Files.filter(f => f.fileName === newFileName).length;
    // If counter >= 2, an error has already been passed to the files because it means
    // 2 files have the same name
    if (counter >= 2) {
        throw 'Error duplicate name already present';
    }
    if (counter === 0) {
        return newFileName
    }
    if (counter === 1) {
        const newName = `${newFileName.split('.')[0]}_${counter}.${newFileName.split('.')[1]}`;
        // Return export_1.csv;
        return checkNameOfTheFile(newName);
        // We need to check if export_1.csv has not been already taken.
        // If so, the new name would be export_1_1.csv, not really pretty but it can be changed easily in this function
    }
};


const CompleteData= {
    fileData: reader.result,
    fileName: checkNameOfTheFile(file.name),
};

How to Increment filename if file exists

This problem is always initializative num = 0 so if file exists, it save file0.jpg and not check whether file0.jpg is exists ?
So, To code work. You should check until available :

int num = 0;
String save = at.getText().toString() + ".jpg";
File file = new File(myDir, save);
while(file.exists()) {
    save = at.getText().toString() + (num++) +".jpg";
    file = new File(myDir, save); 
}

Increment the file name if the file already exists in c#

There is one more problem in your code. Why do you have file names like "New1.txt2","New1.txt2.txt3", "New1.txt2.txt3.txt4"? Because you don't keep initial filename somewhere. So, I'd propose to keep two variables for filenames: for instance, filename_initial and filename_current.

Try something like this:

String filename_initial = @"C:\path\New.txt";
String filename_current = filename_initial;
count = 0;
while (File.Exists(filename_current))
{
    count++;
    filename_current = Path.GetDirectoryName(filename_initial)
                     + Path.DirectorySeparatorChar
                     + Path.GetFileNameWithoutExtension(filename_initial)
                     + count.ToString()
                     + Path.GetExtension(filename_initial);
}

Increment the filename if it already exists when saving files in node.js?

I use something similar to version uploaded image files on disk. I decided to use the "EEXIST" error to increment the number rather than explicitly iterating the files in the directory.

const writeFile = async(filename, data, increment = 0) => {
  const name = `${path.basename(filename, path.extname(filename))}${increment || ""}${path.extname(filename)}`
  return await fs.writeFile(name, data, { encoding: 'utf8', flag: 'wx' }).catch(async ex => {
    if (ex.code === "EEXIST") return await writeFile(filename, data, increment += 1)
    throw ex
  }) || name
}
const unversionedFile = await writeFile("./file.txt", "hello world")
const version1File = await writeFile("./file.txt", "hello world")
const version2File = await writeFile("./file.txt", "hello world")

Dim counter As Integer = 0

Dim newFileName As String = orginialFileName

While File.Exists(newFileName)
    counter = counter + 1
    newFileName = String.Format("{0}({1}", orginialFileName, counter.ToString())
End While