legendaryjs/db/query-builder.js

LegendaryJS – The ultimate backend framework for speed, power, and simplicity.

const { connections } = require('./index');

async function queryDB(db, action, options = {}) {
  switch (db) {
    case 'mongo':
      return handleMongo(action, options);
    case 'postgres':
      return handlePostgres(action, options);
    case 'mysql':
      return handleMySQL(action, options);
    default:
      throw new Error(`Unknown DB engine: ${db}`);
  }
}

// MongoDB
async function handleMongo(action, { model, filter = {}, data = {} }) {
  const Model = require(`./models/${model}`);
  switch (action) {
    case 'find': return await Model.find(filter);
    case 'findOne': return await Model.findOne(filter);
    case 'create': return await Model.create(data);
    case 'update': return await Model.updateMany(filter, { $set: data });
    case 'delete': return await Model.deleteMany(filter);
  }
}

// PostgreSQL
async function handlePostgres(action, { table, filter = {}, data = {} }) {
  const pool = connections.postgres;
  let query = '', values = [];
  switch (action) {
    case 'find':
      const where = Object.keys(filter).map((k, i) => `${k} = $${i + 1}`).join(' AND ');
      values = Object.values(filter);
      query = `SELECT * FROM ${table} ${where ? 'WHERE ' + where : ''}`;
      return (await pool.query(query, values)).rows;
    case 'create':
      const cols = Object.keys(data);
      values = Object.values(data);
      const placeholders = cols.map((_, i) => `$${i + 1}`).join(', ');
      query = `INSERT INTO ${table} (${cols.join(', ')}) VALUES (${placeholders}) RETURNING *`;
      return (await pool.query(query, values)).rows;
    // (other actions can be added similarly)
  }
}

// MySQL
async function handleMySQL(action, { table, filter = {}, data = {} }) {
  const conn = connections.mysql;
  switch (action) {
    case 'find':
      let [rows] = await conn.query(`SELECT * FROM ${table}`);
      return rows;
    case 'create':
      let [result] = await conn.query(`INSERT INTO ${table} SET ?`, data);
      return result;
  }
}

module.exports = { queryDB };