Problem: Normalize Logger Interfaces

Easy

15 min

Adapt inconsistent logging libraries to a single, predictable interface.

Problem statement

Your team’s codebase uses two different logging systems across services:

Some modules use the native console object (console.log, console.error).
Others rely on a custom in-house logger with logInfo() and logError() methods.

The inconsistency causes confusion and brittle integrations. You’ve been tasked to create a unified adapter so that the rest of the system can use a single, predictable interface.

Goal

Implement a LoggerAdapter class that wraps either console or customLogger and exposes these two methods:

.info(message) → routes to the correct info-level method
.error(message) → routes to the correct error-level method

Constraints

The adapter must delegate to the correct underlying method (logInfo or console.log, logError or console.error).
Do not modify the original logger implementations.
The calling code should always use the same LoggerAdapter interface.

Sample output

The examples below illustrate what the output should look like:

Problem: Normalize Logger Interfaces

Easy

15 min

Adapt inconsistent logging libraries to a single, predictable interface.

Problem statement

Your team’s codebase uses two different logging systems across services:

Some modules use the native console object (console.log, console.error).
Others rely on a custom in-house logger with logInfo() and logError() methods.

The inconsistency causes confusion and brittle integrations. You’ve been tasked to create a unified adapter so that the rest of the system can use a single, predictable interface.

Goal

Implement a LoggerAdapter class that wraps either console or customLogger and exposes these two methods:

.info(message) → routes to the correct info-level method
.error(message) → routes to the correct error-level method

Constraints

The adapter must delegate to the correct underlying method (logInfo or console.log, logError or console.error).
Do not modify the original logger implementations.
The calling code should always use the same LoggerAdapter interface.

Sample output

The examples below illustrate what the output should look like:

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Adapt Configuration Sources

Node.js

// Simulated in-house custom logger
const customLogger = {
  logInfo(msg) {
    console.log(`customLogger info: ${msg}`);
  },
  logError(msg) {
    console.error(`customLogger error: ${msg}`);
  }
};
// Your code here
// Example usage
const consoleLogger = new LoggerAdapter(console);
const internalLogger = new LoggerAdapter(customLogger);
consoleLogger.info('Server started');
internalLogger.info('Server started');
consoleLogger.error('Failed to connect');
internalLogger.error('Failed to connect');
/* Expected output:
Server started
customLogger info: Server started
Failed to connect
customLogger error: Failed to connect
*/