Streams vs loading entire file in memory in Node.js - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to read a file using the built-in Node.js module.

Node.js

const fs = require('fs');

fs.[1]('example.txt', (err, data) => {
  if (err) throw err;
  console.log(data.toString());
});

Drag options to blanks, or click blank then click option'

AcreateReadStream

BappendFile

CreadFile

DwriteFile

Attempts:

3 left

💡 Hint

Common Mistakes

Using createReadStream instead of readFile for reading entire file at once.

The readFile method reads the entire file into memory before calling the callback.

2fill in blank

medium

Complete the code to create a readable stream from a file.

Node.js

const fs = require('fs');

const stream = fs.[1]('example.txt');

stream.on('data', chunk => {
  console.log(chunk.toString());
});

Drag options to blanks, or click blank then click option'

AcreateReadStream

BappendFile

CwriteFile

DreadFile

Attempts:

3 left

💡 Hint

Common Mistakes

Using readFile which reads the whole file at once.

createReadStream creates a stream to read the file piece by piece.

3fill in blank

hard

Fix the error in the code to properly handle stream errors.

Node.js

const fs = require('fs');

const stream = fs.createReadStream('example.txt');

stream.on('data', chunk => {
  console.log(chunk.toString());
});

stream.on('[1]', err => {
  console.error('Error:', err);
});

Drag options to blanks, or click blank then click option'

Aclose

Berror

Cend

Dfinish

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'close' or 'end' event to catch errors.

The error event is emitted when the stream encounters an error.

4fill in blank

hard

Fill both blanks to pipe a readable stream into a writable stream.

Node.js

const fs = require('fs');

const readable = fs.createReadStream('input.txt');
const writable = fs.[1]('output.txt');

readable.[2](writable);

Drag options to blanks, or click blank then click option'

AcreateWriteStream

BreadFile

Cpipe

DwriteFile

Attempts:

3 left

💡 Hint

Common Mistakes

Using writeFile instead of createWriteStream for writable stream.

Calling readFile on readable stream.

createWriteStream creates a writable stream, and pipe connects the readable stream to it.

5fill in blank

hard

Fill all three blanks to read a file stream and count chunks received.

Node.js

const fs = require('fs');

const stream = fs.[1]('data.txt');
let count = 0;

stream.on('[2]', chunk => {
  count += 1;
  console.log(`Chunk #$[3] received`);
});

Drag options to blanks, or click blank then click option'

AcreateReadStream

Bdata

Ccount

DreadFile

Attempts:

3 left

💡 Hint

Common Mistakes

Using readFile instead of createReadStream.

Using 'end' event instead of 'data' for chunks.

createReadStream creates the stream, data event fires for each chunk, and count tracks the number of chunks.