Function collectDeclaredIdentifiers

packages/js-runtime/src/ast-walker.ts:45–78

(ast: unknown)

 * Track declared variables/parameters to know what identifiers are "local"
 */
export function collectDeclaredIdentifiers(ast: unknown): Set<string> {
  const declared = new Set<string>();

  walkNode(ast, (node) => {
    // Variable declarations: const x = ..., let y = ..., var z = ...
    if (node.type === 'VariableDeclarator') {
      const id = node.id as Record<string, unknown>;
      if (id.type === 'Identifier') {
        declared.add(id.name as string);
      }
      // Handle destructuring patterns
      if (id.type === 'ObjectPattern') {
        collectPatternIdentifiers(id, declared);
      }
      if (id.type === 'ArrayPattern') {
        collectPatternIdentifiers(id, declared);
      }
    }

    // Function parameters
    if (
      node.type === 'ArrowFunctionExpression' ||
      node.type === 'FunctionExpression' ||
      node.type === 'FunctionDeclaration'
    ) {
      const params = node.params as Array<Record<string, unknown>>;
      for (const param of params) {
        collectPatternIdentifiers(param, declared);
      }
    }
  });

  return declared;
}

/**
 * Collect identifiers from destructuring patterns