Why streams are needed in Node.js - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

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

Node.js

const fs = require('fs');
const readable = fs.createReadStream([1]);

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

A'input.txt'

B'write.txt'

C'output.txt'

D'config.json'

Attempts:

3 left

💡 Hint

Common Mistakes

Using a file name meant for writing instead of reading.

The createReadStream method needs the path of the file to read. Here, 'input.txt' is the correct file to read from.

2fill in blank

medium

Complete the code to pipe data from a readable stream to a writable stream.

Node.js

readableStream.[1](writableStream);

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

Awrite

Bpipe

Csend

Dtransfer

Attempts:

3 left

💡 Hint

Common Mistakes

Using methods that don't exist on streams like 'write' or 'send'.

The pipe method connects a readable stream to a writable stream, sending data automatically.

3fill in blank

hard

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

Node.js

readableStream.on('error', [1]);

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

Aconsole.info

Bconsole.warn

Cconsole.log

Dconsole.error

Attempts:

3 left

💡 Hint

Common Mistakes

Using console.log which is less clear for errors.

Using console.error is best to log errors clearly when a stream emits an error event.

4fill in blank

hard

Fill both blanks to create a writable stream and write data to it.

Node.js

const writable = fs.createWriteStream([1]);
writable.[2]('Hello, streams!');

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

A'output.txt'

Bwrite

Cend

D'input.txt'

Attempts:

3 left

💡 Hint

Common Mistakes

Using the input file name for writing or using the wrong method like 'end' to write data.

Create a writable stream to 'output.txt' and use write to send data to it.

5fill in blank

hard

Fill all three blanks to create a transform stream that modifies data.

Node.js

const { Transform } = require('stream');
const upperCaseTransform = new Transform({
  transform(chunk, encoding, callback) {
    this.push(chunk.toString().[1]());
    callback();
  }
});
readableStream.[2](upperCaseTransform).[3](writableStream);

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

AtoUpperCase

Bpipe

DtoLowerCase

Attempts:

3 left

💡 Hint

Common Mistakes

Using toLowerCase instead of toUpperCase or missing pipe connections.

The transform stream converts data to uppercase using toUpperCase(). Then it pipes data from readable to transform, and from transform to writable.