node .js read file and save string code example

Example 1: node js write file

// fs_write.js

const fs = require('fs');

// specify the path to the file, and create a buffer with characters we want to write
let path = 'ghetto_gospel.txt';
let buffer = new Buffer('Those who wish to follow me\nI welcome with my hands\nAnd the red sun sinks at last');

// open the file in writing mode, adding a callback function where we do the actual writing
fs.open(path, 'w', function(err, fd) {
    if (err) {
        throw 'could not open file: ' + err;
    }

    // write the contents of the buffer, from position 0 to the end, to the file descriptor returned in opening our file
    fs.write(fd, buffer, 0, buffer.length, null, function(err) {
        if (err) throw 'error writing file: ' + err;
        fs.close(fd, function() {
            console.log('wrote the file successfully');
        });
    });
});

Example 2: node js store values in file

var fs = require('fs');

var myOptions = {
  name: 'Avian',
  dessert: 'cake'
  flavor: 'chocolate',
  beverage: 'coffee'
};

var data = JSON.stringify(myOptions);

fs.writeFile('./config.json', data, function (err) {
  if (err) {
    console.log('There has been an error saving your configuration data.');
    console.log(err.message);
    return;
  }
  console.log('Configuration saved successfully.')
});