updateExportUsage = (node) => {
      if (ignoredFiles.has(file)) {
        return;
      }

      let exports = exportList.get(file);

      // new module has been created during runtime
      // include it in further processing
      if (typeof exports === 'undefined') {
        exports = new Map();
      }

      const newExports = new Map();
      const newExportIdentifiers = new Set();

      node.body.forEach(({ type, declaration, specifiers }) => {
        if (type === EXPORT_DEFAULT_DECLARATION) {
          newExportIdentifiers.add(IMPORT_DEFAULT_SPECIFIER);
        }
        if (type === EXPORT_NAMED_DECLARATION) {
          if (specifiers.length > 0) {
            specifiers.forEach((specifier) => {
              if (specifier.exported) {
                newExportIdentifiers.add(specifier.exported.name || specifier.exported.value);
              }
            });
          }
          forEachDeclarationIdentifier(declaration, (name) => {
            newExportIdentifiers.add(name);
          });
        }
      });

      // old exports exist within list of new exports identifiers: add to map of new exports
      exports.forEach((value, key) => {
        if (newExportIdentifiers.has(key)) {
          newExports.set(key, value);
        }
      });

      // new export identifiers added: add to map of new exports
      newExportIdentifiers.forEach((key) => {
        if (!exports.has(key)) {
          newExports.set(key, { whereUsed: new Set() });
        }
      });

      // preserve information about namespace imports
      const exportAll = exports.get(EXPORT_ALL_DECLARATION);
      let namespaceImports = exports.get(IMPORT_NAMESPACE_SPECIFIER);

      if (typeof namespaceImports === 'undefined') {
        namespaceImports = { whereUsed: new Set() };
      }

      newExports.set(EXPORT_ALL_DECLARATION, exportAll);
      newExports.set(IMPORT_NAMESPACE_SPECIFIER, namespaceImports);
      exportList.set(file, newExports);
    }
only useful for tools like vscode-eslint

update lists of existing exports during runtime