Writing to files in Node.js

I've been trying to find a way to write to a file when using Node.js, but with no success. How can I do that?

var path = 'public/uploads/file.txt',
buffer = new Buffer("some content\n");

fs.open(path, 'w', function(err, fd) {
if (err) {
throw 'error opening file: ' + err;
}

fs.write(fd, buffer, 0, buffer.length, null, function(err) {
if (err) throw 'error writing file: ' + err;
fs.close(fd, function() {
console.log('file written');
})
});
});

You can of course make it a little more advanced. Non-blocking, writing bits and pieces, not writing the whole file at once:

var fs = require('fs');
var stream = fs.createWriteStream("my_file.txt");
stream.once('open', function(fd) {
stream.write("My first row\n");
stream.write("My second row\n");
stream.end();
});

You can use library `easy-file-manager`

install first from npm
`npm install easy-file-manager`

Sample to upload and remove files

var filemanager = require('easy-file-manager')
var path = "/public"
var filename = "test.jpg"
var data; // buffered image

filemanager.upload(path,filename,data,function(err){
if (err) console.log(err);
});

filemanager.remove(path,"aa,filename,function(isSuccess){
if (err) console.log(err);
});

var fs = require('fs');
fs.writeFile(path + "\\message.txt", "Hello", function(err){
if (err) throw err;
console.log("success");
});

For example : read file and write to another file :

var fs = require('fs');
var path = process.cwd();
fs.readFile(path+"\\from.txt",function(err,data)
{
if(err)
console.log(err)
else
{
fs.writeFile(path+"\\to.text",function(erro){
if(erro)
console.log("error : "+erro);
else
console.log("success");
});
}
});

Here is the sample of how to read file csv from local and write csv file to local.

var csvjson = require('csvjson'),
fs = require('fs'),
mongodb = require('mongodb'),
MongoClient = mongodb.MongoClient,
mongoDSN = 'mongodb://localhost:27017/test',
collection;

function uploadcsvModule(){
var data = fs.readFileSync( '/home/limitless/Downloads/orders_sample.csv', { encoding : 'utf8'});
var importOptions = {
delimiter : ',', // optional
quote : '"' // optional
},ExportOptions = {
delimiter : ",",
wrap : false
}
var myobj = csvjson.toSchemaObject(data, importOptions)
var exportArr = [], importArr = [];
myobj.forEach(d=>{
if(d.orderId==undefined || d.orderId=='') {
exportArr.push(d)
} else {
importArr.push(d)
}
})
var csv = csvjson.toCSV(exportArr, ExportOptions);
MongoClient.connect(mongoDSN, function(error, db) {
collection = db.collection("orders")
collection.insertMany(importArr, function(err,result){
fs.writeFile('/home/limitless/Downloads/orders_sample1.csv', csv, { encoding : 'utf8'});
db.close();
});
})
}

uploadcsvModule()

I liked *[Index of ./articles/file-system][1]*.

It worked for me.

See also *[How do I write files in node.js?][2]*.

fs = require('fs');
fs.writeFile('helloworld.txt', 'Hello World!', function (err) {
if (err)
return console.log(err);
console.log('Wrote Hello World in file helloworld.txt, just check it');
});

Contents of helloworld.txt:

Hello World!

[1]:

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[2]:

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Update:
As in Linux node write in current directory , it seems in some others don't, so I add this comment just in case :
Using this `ROOT_APP_PATH = fs.realpathSync('.'); console.log(ROOT_APP_PATH);` to get where the file is written.

> ### [`fs.createWriteStream(path[,options])`](

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)
>
> `options` may also include a `start` option to allow writing data at some position past the beginning of the file. Modifying a file rather than replacing it may require a `flags` mode of `r+` rather than the default mode `w`. The encoding can be any one of those accepted by [Buffer](

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).
>
> If `autoClose` is set to true (default behavior) on `'error'` or `'finish'` the file descriptor will be closed automatically. If `autoClose` is false, then the file descriptor won't be closed, even if there's an error. It is the application's responsibility to close it and make sure there's no file descriptor leak.
>
> Like [ReadStream](

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), if `fd` is specified, [WriteStream](

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) will ignore the `path` argument and will use the specified file descriptor. This means that no `'open'` event will be emitted. `fd` should be blocking; non-blocking `fd`s should be passed to [net.Socket](

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).
>
> If `options` is a string, then it specifies the encoding.

After, reading this long article. You should understand how it works.
So, here's an example of `createWriteStream()`.

/* The fs.createWriteStream() returns an (WritableStream {aka} internal.Writeable) and we want the encoding as 'utf'-8 */
/* The WriteableStream has the method write() */
fs.createWriteStream('out.txt', 'utf-8')
.write('hello world');

OK, it's quite simple as Node has built-in functionality for this, it's called `fs` which stands for **File System** and basically, **NodeJS File System module**...

So first require it in your **server.js** file like this:

var fs = require('fs');

`fs` has few methods to do write to file, but my preferred way is using `appendFile`, this will append the stuff to the file and if the file doesn't exist, will create one, the code could be like below:


fs.appendFile('myFile.txt', 'Hi Ali!', function (err) {
if (err) throw err;
console.log('Thanks, It\'s saved to the file!');
});

The answers provided are dated and a newer way to do this is:

const fsPromises = require('fs').promises
await fsPromises.writeFile('/path/to/file.txt', 'data to write')

[see documents here for more info](

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)