fs module - appendFile()

 fs module:

The Node.js file system module allows you to work with the file system on your computer.

appendFile(): 

Syntax:

fs.appendFile(path, data, options, callback);

appendFile() method creates a new file and inserts content inside the file. If the file exists, then it will only append the content with old content.

    var fs = require("fs");

    fs.appendFile("latest.txt", "Mozahedul Islam", function (err) {

      if (err) {

        throw err;

        console.log("Failed");

      }

    });

appendFileSync(): 

Synchronously append data to a file, creating the file if it does not yet exist.

Syntax:

fs.appendFileSync(path, data, options);

  

    try {

      fs.appendFileSync("message.txt", "data to append");

      console.log('The "data to append" was appended to file!');

    } catch (err) {

      /* Handle the error */

    }