VIP20/19_Node.js/day-5/code/koa-demo/db/index.js

import { createPool } from 'mysql2/promise';
import { DB_CONFIG } from '../app.config.mjs';

const pool = createPool(DB_CONFIG);

export async function query(sql, values) {
  try {
    let [res] = await pool.query(sql, values);
    return res;
  } catch (error) {
    console.log('====', error);
    return Promise.reject(false);
  }
}
// 定义一个数据库的中间件：作用使得每个中间件函数的ctx对象都可以具有query方法
export function DBMiddleware(
  { queryname } = {
    queryname: 'execute',
  }
) {
  return async (ctx, next) => {
    ctx.app.context[queryname] = query;
    await next();
  };
}

export default pool;