npm install sequelize-querystring-converter

yarn add sequelize-querystring-converter

const queryStringConverter = require('sequelize-querystring-converter');
const obj = queryStringConverter.convert({
  query: {
    category: 'Shirts',
    name: 'substring:Shirt',
    price: 'between:0,5000',
    discount: 'gte:10',
    brand: 'in:Nike,New Balance,Puma',
    color: 'black',
    sort: '-price',
    offset: 15,
    limit: 15
  },
  basedProperties: ['name', 'price', 'discount', 'brand']
});
// category property will be ignored because it's not defined in basedProperties
// obj = {
//  where: {
//    name: { [Symbol(substring)]: 'Shirt' },
//    price: { [Symbol(between)]: ['0', '5000'] },
//    discount: { [Symbol(gte)]: '10' },
//    brand: { [Symbol(10)]: ['Nike', 'New Balance', 'Puma'] }
//    color: 'black'
//  },
//  order: [['price', 'DESC']],
//  offset: 15,
//  limit: 15,
// };

const querystringConverter = require('sequelize-querystring-converter');
const { Product } = require('../models');
async function listProducts = async (req, res) {
  // assuming api request would be like this
  // base_url/products?brand=Nike&sort=-createdAt
  // then query object will be equal to this
  // { brand: 'Nike', sort: '-createdAt' }
  const { query } = req;
  try {
    const criteria = querystringConverter.convert({ query });
    // criteria = { where: { brand: 'Nike' }, order: [ ['createdAt', 'DESC'] ]}
    const products = await Product.findAll(criteria);
    // products = [
    // {id: 2, name: 'Sample Product 2', brand: 'Nike', createdAt: '2019-07-18 08:25:30'},
    // {id: 1, name: 'Sample Product 1', brand: 'Nike', createdAt '2019-07-16 10:00:01}
    // ...
    //]
    res.status(200).json(products);
  } catch (error) {
    res.status(400).json(error);
  }
}
module.exports = { listProducts };