writefile fs code example

Example 1: writefile in node js

// writefile.js

const fs = require('fs');

let lyrics = 'But still I\'m having memories of high speeds when the cops crashed\n' + 
             'As I laugh, pushin the gas while my Glocks blast\n' + 
             'We was young and we was dumb but we had heart';

// write to a new file named 2pac.txt
fs.writeFile('2pac.txt', lyrics, (err) => {
    // throws an error, you could also catch it here
    if (err) throw err;

    // success case, the file was saved
    console.log('Lyric saved!');
});

Example 2: nodejs readfile

const fs = require('fs');

fs.readFile('/Users/joe/test.txt', 'utf8' , (err, data) => {
  if (err) {
    console.error(err);
    return
  }
  console.log(data);
});

Example 3: fs.writefile

const fs = require('fs');

fs.writeFile("/tmp/test", "Hey there!", function(err) {
    if(err) {
        return console.log(err);
    }
    console.log("The file was saved!");
}); 

// Or
fs.writeFileSync('/tmp/test-sync', 'Hey there!');

Example 4: writefile in node js

// write_stream.js

const fs = require('fs');

let writeStream = fs.createWriteStream('secret.txt');

// write some data with a base64 encoding
writeStream.write('aef35ghhjdk74hja83ksnfjk888sfsf', 'base64');

// the finish event is emitted when all data has been flushed from the stream
writeStream.on('finish', () => {
    console.log('wrote all data to file');
});

// close the stream
writeStream.end();

Example 5: writefile in node js

fs.writeFile('2pac.txt', 'Some other lyric', 'ascii', callback);

Example 6: writefile in node js

// 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');
        });
    });
});