Node.js Stream Example

var fs = require('fs')

// create a random file with random data

var write = fs.writeFileSync('input.txt', "Written to input.txt")

// create read stream *******************************

var stream = fs.createReadStream("input.txt");

// set encoding

stream.setEncoding('utf8')

// handle the events of read stream i.e. data , end , error
var data = '';
// data event
stream.on('data', function(chunk) {

    data += chunk;
})

// end event 
stream.on('end', function() {
    console.log(data);
})

// error event 
stream.on('error', function(err) {
    console.log(err);
})

// create writeStream ***************************

var write = fs.createWriteStream('output.txt');

// create a variable with random data 
var data = 'data to be written to output.txt file'

// write data to output file with utf8 encoding 
write.write(data, 'utf8')

// handle events of the write stream finish, error 
// finish
write.on('finish', function() {
    console.log("Data Written");
})

// error event
write.on('error', function(err) {
    console.log("Error Writing data")
})


// using pipe ***************** Used to read from one stream and write to another stream

// create a read stream 

var readPi = fs.createReadStream('input.txt');

var writePi = fs.createWriteStream('outputnew.txt');

readPi.pipe(writePi);

// handle events of readPi and writePi

readPi.on("error", function(error) {
    console.log(error.stack)
})
readPi.on("end", function() {
    console.log("Reading Completed for piping")
})

writePi.on("finish", function() {
    console.log("Writing completed for piping")
})
writePi.on("error", function() {
    console.log(error.stack)
})