Why would a JavaScript debugger not show the viewData variable in the inspection tool when stopped at line 06?

In the context of JavaScript debugging within Salesforce B2C Commerce, if the viewData variable is not visible in the inspection tool at a breakpoint, it is often due to a scope issue related to variable declaration. When a variable is assigned a value but not declared properly using the correct keywords (like var, let, or const), it can lead to what is known as an "undefined" state in the current scope, making it unavailable for inspection.

When the JavaScript engine processes a script, it evaluates variable declarations and their scopes. If a variable is assigned but is missing its declaration, it does not get registered in the current lexical environment's scope, resulting in its invisibility in the debugger at that moment. This explains why the inspection tool cannot show the viewData variable if it has been omitted from the declaration.

The issue is not about the variable being declared but not assigned, as that wouldn't result in a failure to show the variable. Similarly, cache middleware validity is irrelevant to this specific context, and reserved names do not typically prevent a variable from being inspected if they are properly declared. Thus, the most accurate reason for the viewData variable's absence in the debugger relates to the assignment without declaration, facilitating its limited visibility in the inspection