Your first program
- Node.js course
- Beginner
- Lesson 2/116
- 4 min
Learn to run a script with node and use console.log.
Your first program
In Node.js, a program is written in a file with the .js extension. For example hello.js. To run the file, you type node hello.js in the terminal.
To print something to the screen, you use console.log(...). The value inside the parentheses is printed and a newline is added automatically at the end.
This is the most basic Node.js output. Let us try it now.
Running a file
To run a JavaScript file, you use the node command in the terminal. For example, node hello.js executes the hello.js file and runs all the code inside it in order.
If the file does not exist, Node.js gives an error message. If it exists, the content is read, compiled by V8 and executed; console.log calls appear in the terminal.
This simple flow is the basis of everyday Node.js use.
Practice Print two lines
Write two console.log calls: print Hello on the first line and Node.js on the second.
Starter code
// Print two linesSample solution
console.log("Hello");
console.log("Node.js");Expected output
Hello Node.js
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 console.log call
To print 'Hello' to the screen: ____("Hello");To print 'Hello' to the screen: console.log("Hello");Explanation: console.log prints to the screen.
2 What does the node command do?
- Loads and runs the JavaScript file Correct answer
- Packages the JavaScript file
- Opens the JavaScript file in a browser
- Deletes the JavaScript file
Explanation: The node command loads and runs the file.
3 Match the program parts
| Term | Meaning |
|---|---|
hello.js |
Source file |
node |
Run command |
console.log |
Output writing |
.js |
File extension |