如何将获取请求返回的数据存储到变量中？

Question

即使我在数据库中有匹配的条目，我也会得到错误的空值。

谢谢。

const express = require("express");
const router = express.Router();
const con = require("../config/keys");
const Validator = require("validator");
const isEmpty = require("./is-empty");

module.exports = function checkIfExists(data, table) {
  let errors = {};

  router.get(`/tools/${table}`, (req, res) => {
    con.query(
      `SELECT * FROM ${table} WHERE particulars = ${data}`,
      (err, result) => {
        if (err)
          return res
            .status(400)
            .json({ errors: "Failed to connect with database" });

        newData = result;
        newData.particulars = !isEmpty(newData.particulars)
          ? newData.particulars
          : "";

        if (!Validator.isEmpty(newData.particulars)) {
          return (errors.particulars = "Particulars already exists");
        }
      }
    );
  });

  return {
    errors,
    isUnique: isEmpty(errors)
  };
};

预期结果：当数据库中存在现有的特定项时，我想将错误放入错误对象中。