Running scripts with node command in Node.js - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to run a Node.js script named app.js from the command line.

Node.js

node [1]

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

Aapp.js

Brun.js

Cindex.html

Dscript.py

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to run a non-JavaScript file like script.py with node.

Forgetting to include the script file name after node.

To run a Node.js script, you use the node command followed by the script file name. Here, app.js is the script to run.

2fill in blank

medium

Complete the command to run a script named server.js located in the src folder.

Node.js

node [1]

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

Asrc\server.js

Bsrc/server.js

Cserver.js

D./server.js

Attempts:

3 left

💡 Hint

Common Mistakes

Using backslashes \ which may not work on all systems.

Omitting the folder path and just typing the file name.

To run a script inside a folder, include the relative path with forward slashes. Here, src/server.js points to the script inside the src folder.

3fill in blank

hard

Fix the error in the command to run app.js when the user typed node app.

Node.js

node [1]

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

Aapp.js

Bapp.jsx

Capp

Dapp.json

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting the .js extension.

Trying to run files with wrong extensions like .jsx or .json.

Node.js requires the full file name including the .js extension to run the script correctly.

4fill in blank

hard

Fill both blanks to run a script named index.js located in the scripts folder using a relative path.

Node.js

node [1]/[2]

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

Ascripts

Bindex.js

Csrc

Dmain.js

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping folder and file names.

Using wrong folder or file names.

The correct relative path is scripts/index.js. The first blank is the folder name, the second is the script file.

5fill in blank

hard

Fill all three blanks to run a script named server.js inside the src folder inside the app folder located in the current directory.

Node.js

node ./[1]/[2]/[3]

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

Aapp

Bsrc

Cserver.js

Dmain.js

Attempts:

3 left

💡 Hint

Common Mistakes

Missing the current directory prefix ./.

Using wrong folder or file names.

Swapping the order of folders and file.

The path ./app/src/server.js runs the script inside nested folders. The first blank is the app folder, second is src, third is the script file.

Practice

1. What does the node command do when you run node script.js in your terminal?

easy

A. It uploads script.js to a web server.

B. It opens the script.js file in a text editor.

C. It compiles script.js into a binary executable.

D. It runs the JavaScript code inside the file script.js using Node.js.

Solution

1. Step 1: Understand the purpose of the node command

   The node command runs JavaScript files using the Node.js runtime environment.

2. Step 2: Analyze the command node script.js

   This command tells Node.js to execute the code inside the file named script.js.

3. Final Answer:

   It runs the JavaScript code inside the file script.js using Node.js. -> Option D

4. Quick Check:

   Running node file.js executes the file [OK]

Hint: Node runs JavaScript files given as arguments [OK]

Common Mistakes:

• Thinking node opens files in editors
• Confusing node with a compiler
• Assuming node uploads files

2. Which of the following is the correct way to run a JavaScript file named app.js using Node.js?

easy

A. node run app.js

B. node app.js

C. run node app.js

D. execute app.js with node

Solution

1. Step 1: Recall the correct syntax for running scripts with Node.js

   The correct syntax is node filename.js without extra words.

2. Step 2: Check each option

   node app.js matches the correct syntax exactly: node app.js.

3. Final Answer:

   node app.js -> Option B

4. Quick Check:

   Correct command syntax is node filename.js [OK]

Hint: Use 'node' followed directly by the filename [OK]

Common Mistakes:

• Adding extra words like 'run' or 'execute'
• Swapping order of 'node' and filename
• Using commands not recognized by Node.js

3. Given the file hello.js with this content:

console.log('Hello, Node!');

What will be the output when running node hello.js?

medium

A. Hello, Node!

B. console.log('Hello, Node!');

C. SyntaxError

D. No output

Solution

1. Step 1: Understand what console.log does

   The console.log function prints the text inside the parentheses to the terminal.

2. Step 2: Predict the output of running node hello.js

   Running the file executes the code and prints 'Hello, Node!' to the terminal.

3. Final Answer:

   Hello, Node! -> Option A

4. Quick Check:

   console.log prints text to terminal [OK]

Hint: console.log prints text when run with node [OK]

Common Mistakes:

• Expecting code to print the code itself
• Thinking node throws syntax errors for valid code
• Assuming no output without browser

4. You try to run node myscript.js but get an error: Error: Cannot find module './myscript.js'. What is the most likely cause?

medium

A. The file myscript.js does not exist in the current directory.

B. Your JavaScript code inside myscript.js has a syntax error.

C. You typed node myscript.js incorrectly; it should be node run myscript.js.

D. Node.js is not installed on your computer.

Solution

1. Step 1: Understand the error message

   The error says Node.js cannot find the file myscript.js in the current folder.

2. Step 2: Identify the cause

   This usually means the file is missing or the path is wrong, not that Node.js is missing or the code has syntax errors.

3. Final Answer:

   The file myscript.js does not exist in the current directory. -> Option A

4. Quick Check:

   File missing causes 'Cannot find module' error [OK]

Hint: Check file exists in current folder before running [OK]

Common Mistakes:

• Assuming Node.js is not installed from this error
• Adding extra words to the node command
• Confusing file not found with syntax errors

5. You have two files:

index.js:
console.log('Start');
require('./helper.js');
console.log('End');

helper.js:
console.log('Helper loaded');

What will be the output when you run node index.js?

hard

A. Start
End
Helper loaded

B. Helper loaded
Start
End

C. Start
Helper loaded
End

D. SyntaxError

Solution

1. Step 1: Understand the order of execution in index.js

   The code first prints 'Start', then loads and runs helper.js, then prints 'End'.

2. Step 2: Trace the output step-by-step

   First, 'Start' is printed. Then helper.js runs and prints 'Helper loaded'. Finally, 'End' is printed.

3. Final Answer:

   Start Helper loaded End -> Option C

4. Quick Check:

   require runs the imported file immediately [OK]

Hint: require runs the file immediately in order [OK]

Common Mistakes:

• Assuming require runs after all code
• Mixing output order
• Expecting syntax errors without mistakes