如何在AST中获取typeof变量？

const parser = require("@babel/parser");
const traverse = require("@babel/traverse").default;

const code = `typeof foo === 'string'`;

const ast = parser.parse(code, {
  sourceType: "module",
});

let typeofVariables = [];

traverse(ast, {
  UnaryExpression(path) {
    if (path.node.operator === "typeof") {
      if (path.node.argument.type === "Identifier") {
        typeofVariables.push(path.node.argument.name);
      } else if (path.node.argument.type === "Literal") {
        typeofVariables.push(path.node.argument.value);
      }
    }
  },
});

console.log(typeofVariables);