$logProvider debug logging default off from AngularJS 1.5

Handling Debug Logging Defaults

In AngularJS 1.5, $logProvider.enableDebugLogging defaults to false. This change suppresses $log.debug() calls from both the framework internals and third-party modules to reduce console noise. Because this is a provider configuration, it must be set during the module config phase; it cannot be toggled at runtime.

Appropriate Use in Non-Production Builds

Enabling debug logging is appropriate for non-production builds under the following conditions:

• Integration Testing: When verifying that third-party modules are initializing correctly or reaching specific internal states.
• Local Development: When debugging complex data-binding or digest cycle issues where framework-level debug traces are required.
• Regression Testing: When transitioning from AngularJS 1.4 to 1.5+ to ensure that the suppression of debug logs hasn't hidden critical operational warnings emitted via the debug channel.

Impact on Dynamic Modules and Visibility

The config-phase restriction means that any module loaded dynamically (e.g., via lazy loading or asynchronous script injection) will inherit the global $logProvider state established at application bootstrap. If enableDebugLogging was set to false during the initial config phase, diagnostics from dynamically loaded modules using $log.debug will remain invisible.

Regarding operational messages: Yes, disabling debug logging can obscure critical information. Some third-party modules incorrectly use $log.debug for operational alerts or state changes that are not strictly "debug" in nature. If a module uses $log.debug instead of $log.warn or $log.error for important notifications, those messages will be silenced by default in 1.5+.

Implementation Steps

To enable debug logging for development environments while keeping it disabled for production, use a conditional check during the config phase:

angular.module('myApp', [])
  .config(['$logProvider', function($logProvider) {
    // Replace with your environment detection logic
    if (window.env === 'development') {
      $logProvider.enableDebugLogging(true);
    }
  }]);

Verification

To verify the current state of the logger in the browser console, you can inject the $log service via the Angular debug tool or a temporary controller:

// In the browser console (assuming angular is global)
angular.element(document.body).injector().get('$log').debug('Debug logging is active');

If no output appears, debug logging is disabled.

Diagnostic Detail Required: Are you using a custom wrapper for the $log service or a third-party logging library (like ngLog)? This may override the $logProvider settings.