fix: incorrect print level for the DefaultLogger

[duyhungtnn]

I found this issue while investigating an error in OpenFeature Node.js e2e
I saw a log with the prefix “error,” but it was not actually an error—it was a misleading message caused by incorrect logic in the DefaultLogger..

Issues with the Original DefaultLogger Implementation

• Incorrect Console Method Usage
  All log messages, regardless of level (debug, info, warn, error), were output using console.error. This caused all logs to appear as errors, even when they were informational or debug messages.

• Log Message Suppression
  The logger did not output messages if only a single argument was provided (e.g., logger.error('something')), due to an unnecessary args.length === 1 check.

• Static Prefix Assignment
  The log message prefix was set based on the logger’s configured level, not the actual level of the message being logged. This could result in misleading prefixes.

• Unnecessary Complexity
  The use of a separate write() method added complexity and made the code harder to maintain, especially since the logic could be handled more simply and clearly.

[Copilot]

Pull Request Overview

This PR fixes critical logging issues in the DefaultLogger class, correcting incorrect console method usage and log level handling that was causing all messages to appear as errors with misleading prefixes.

• Replaces incorrect static prefix assignment with dynamic level-based prefixes
• Fixes console method selection to use appropriate methods (error, warn, info, debug) instead of always using console.error
• Removes unnecessary single-argument suppression and simplifies the logging logic

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[duyhungtnn]

please help me to take a look @cre8ivejp

[duyhungtnn]

it was like

destroy finished Timeout {
      _idleTimeout: -1,
      _idlePrev: null,
      _idleNext: null,
      _idleStart: 5616,
      _onTimeout: null,
      _timerArgs: undefined,
      _repeat: 30000,
      _destroyed: true,
      [Symbol(refed)]: true,
      [Symbol(kHasPrimitive)]: false,
      [Symbol(asyncId)]: 644,
      [Symbol(triggerId)]: 0
    }

It made me feel like something bad had happened, but it hadn’t.