What is the best way to change the code?

Question

JavaScript

What can be done about it? either do it synchronously or wait like that?
or somehow combine requests into one

let categories,products,seasons,sizes
    categoryModel.find({}).then(a=>{
      categories=a
      productModel.find({}).then(b=>{
        products=b
        seasonModel.find({}).then(c=>{
          seasons=c
          sizeModel.find({}).then(d=>{
            sizes=d
            res.render("admin",{categories,products,seasons,sizes})
          })
        })
      })
    })

Answer 1

Approximately like this:

const queries = [
    categoryModel.find({}),
    productModel.find({}),
    seasonModel.find({}),
    sizeModel.find({})
];
Promise.all(queries).then(result => {
    console.log(result);
}).catch(err => {
    throw err;
});

Answer 2

Promise.all
or await if they must be executed sequentially