When to Use What: A Guide to Node.js Logging Methods (console.log, process.stdout.write, and Beyond)

Data Type Handling:

Output Formatting:

Here's an analogy:

When to Use Which:

// Using console.log (simple and formatted)
console.log("Hello, world!");
console.log(42);  // Number gets displayed as a number

// Using process.stdout.write (manual control)
process.stdout.write("Hello, ");
process.stdout.write("world!\n");  // Need to add newline manually

// Output:
// Hello, world!
// 42
// Hello, world!

Example 2: Printing Objects

// Using console.log (formats objects)
const person = { name: "Alice", age: 30 };
console.log(person);

// Using process.stdout.write (prints raw string)
process.stdout.write(JSON.stringify(person) + "\n");  // Convert to string first

// Output:
// { name: 'Alice', age: 30 }
// {"name":"Alice","age":30}

Example 3: Custom Formatting

// Using console.log (automatic formatting)
console.log("Product ID:", 123, "Name:", "T-Shirt");

// Using process.stdout.write (manual formatting)
process.stdout.write("Product ID: ");
process.stdout.write(123.toString() + " ");  // Convert number to string
process.stdout.write("Name: T-Shirt\n");

// Output:
// Product ID: 123 Name: T-Shirt
// Product ID: 123 Name: T-Shirt

• Benefits: Powerful features like log levels (debug, info, warn, error), structured logging (easier to parse), file logging (write logs to files), and integrations with external services.
• Examples: winston, pino, bunyan (search for them using a web search engine).
• Use Cases: When you need more advanced logging functionalities beyond basic console output, especially in complex applications.

debugger Keyword:

• Benefits: Pauses code execution at the current line, allowing you to inspect variables and the call stack in the debugger window.
• Use Cases: Useful for debugging purposes to step through code line by line and examine values.

console Object Methods:

• console.error: Prints a message to the console as an error, often displayed in red. Useful for highlighting potential issues.
• console.warn: Prints a message as a warning, often displayed in yellow. Good for indicating non-critical issues.
• console.table: Formats data structures like arrays or objects into a tabular format for easier visualization.
• console.group and console.groupEnd: Create collapsible groups in the console output, helpful for organizing related logs.
• console.time and console.timeEnd: Measure execution time between two points in your code.

Choosing the Right Method:

• For basic development logging, console.log is a good starting point.
• For advanced logging needs, explore third-party libraries.
• Use debugger during debugging sessions.
• Utilize other console methods for specific formatting or highlighting.