Variable hasCommonJSFilename`Const`

hasCommonJSFilename: boolean = ...

Determines whether the current runtime provides the CommonJS __filename variable.

Remarks

In CommonJS environments, Node.js injects a module-scoped __filename variable representing the absolute path of the current module file.
In pure ESM environments, __filename does not exist.
This helper allows environment-aware branching while remaining testable (e.g., via mocking in unit tests).

Returns

true if __filename is available in the current runtime; otherwise false.

Example

if (hasCommonJSFilename) {
  console.log("Running in CommonJS environment");
} else {
  console.log("Running in ESM environment");