Handling complex query parameters Express.Js

I’m making REST APIS with Express.js I have the following express route:

/api/customer

I added multiple query params to the route like this:

/api/customer?name=jake
/api/customer?country=america
/api/customer?name=jake&country=america 
/api/customer?name=jake&limit=10

In my controllers I handle all of these with If and there are so many cases I feel that this method would not scale, is there a better way of handling this ?

This is the code for my controller, I’m using Sequelize to query the database:

async function getAllCustomer(queryLimit, page) {  
  const customers = await Customer.findAll({
    limit: queryLimit ? parseInt(queryLimit) : null,
    offset: page ? parseInt(queryLimit) * parseInt(page) : null
  });
  
  return customers;
}

async function getCustomerByFirstName(name, queryLimit, page) {
  return await Customer.findAll({
    where: {
      firstName: name,
    }
  })
}

async function getCustomerByAddress(address) {
  return await Customer.findAll({
    where: {
      customerAddress: address
    }
  })
}

async function getCustomerByNameAddress(name, address) {
  return await Customer.findAll({
    where: {
      [Op.and]: [
        {firstName: name},
        {customerAddress: address}
      ]
    }
  })
}

async function getCustomer(req, res) {
  const page = req.query.page;
  const queryLimit = req.query.limit;
  const name = req.query.name;
  const address = req.query.address;
  
  let customers;
  /* User want to find first names */
  if (name && !address) {
    const names = name.split(",")

    customers = await getCustomerByFirstName(names, queryLimit, page)


    res.status(200).send(customers)
    return;
  }

  /* User want to find addresses */
  if (!name && address) {
    const addresses = address.split(",")
    customers = await getCustomerByAddress(addresses, queryLimit, page)
    res.status(200).send(customers)
    return;
  }

  /* User want to mix both */
  if (name && address) {
    const names = name.split(",")
    const addresses = address.split(",")
    customers = await getCustomerByNameAddress(names, addresses, queryLimit, page)    

    res.status(200).send(customers)
    return;
  }

  if (!name && !address) {
    customers = await getAllCustomer(queryLimit, page)
    res.status(200).send(customers)
    return;
  }
}

Answer

You could do something like this:

async function getCustomer(req, res) {
  const page = req.query.page;
  const queryLimit = req.query.limit;
  const name = req.query.name;
  const address = req.query.address;
  
  let query = { };
  if(name) {
    query.firstName = name;
  }
  
  if(address) {
    query.address = address;
  }
  
  let customers = await getCustomers(query, queryLimit, page);
  res.status(200).send(customers)
  return;
}

async function getCustomers(query, queryLimit, page) {  
  const customers = await Customer.findAll({
    where: query,
    limit: queryLimit ? parseInt(queryLimit) : null,
    offset: page ? parseInt(queryLimit) * parseInt(page) : null
  });
  
  return customers;
}

BTW, in your code, the functions getCustomerByFirstName, getCustomerByAddress and getCustomerByNameAddress are expecting to receive name and address as string parameter, but you are passing names and addresses array. This might lead to errors…