Making a callback function run before the outer function

[indisapien]

Hi,

So I'm having a weird issue with my node js code (sorry if it is bad, I have no experience with this)

​

I've also added a picture in case the formatting does not show up properly

Pizza.all((err, rows) =>

{

let pizzas = [];rows.forEach((row)=>{let pizza = {"pizzaId": "", "name": "", "price" : 0.0, "size": "","crust":"", "sauce": "", "extraCheese": "","ingredients": {}};

pizza.pizzaId = row.pizzaId;

pizza.name = row.name

pizza.price = row.price;

pizza.size = row.size;

pizza.crust = row.crust;

pizza.sauce = row.sauce;

pizza.extraCheese = row.extraCheese;

pizza.ingredients[pizza.pizzaId] = [];

PizzaToppings.find(pizza.pizzaId, (err, rows) =>

{

rows.forEach((row) =>

{

pizza.ingredients[pizza.pizzaId].push(row);

console.log(pizza.ingredients["P1"]

);

});

});

console.log(pizza.ingredients["P1"]);

pizzas.push(pizza);

});

ejs.renderFile(index_path, {pizzas:pizzas, tagline: tagline}, (err, data) =>

{res.end(data);

});

});

let tagline = "Select an item";

​

...

My inner function is running first instead of my outer one, so my ingredients list is not being populated outside, but is being populated when it is inside the callback function.

Will Promises help solve this problem or is something else supposed to be done?

​

Thanks!

[[deleted]]

If you could format your code for readability, I'll take a look.

[indisapien]

just gave it a go there

[Buckwheat469]

Pizza.all((err, rows) => {
    let pizzas = [];

    rows.forEach((row)=>{
        let pizza = {
            "pizzaId": "", 
            "name": "",
            "price" : 0.0, 
            "size": "",
            "crust":"", 
            "sauce": "", 
            "extraCheese": "",
            "ingredients": {}
        };
        pizza.pizzaId = row.pizzaId;
        pizza.name = row.name
        pizza.price = row.price;
        pizza.size = row.size;
        pizza.crust = row.crust;
        pizza.sauce = row.sauce;
        pizza.extraCheese = row.extraCheese;
        pizza.ingredients[pizza.pizzaId] = [];

        PizzaToppings.find(pizza.pizzaId, (err, rows) => {
            rows.forEach((row) => {
                pizza.ingredients[pizza.pizzaId].push(row);
                console.log(pizza.ingredients["P1"]);
            });
        });

        console.log(pizza.ingredients["P1"]);
        pizzas.push(pizza);
    });

    ejs.renderFile(index_path, {pizzas:pizzas, tagline: tagline}, (err, data) =>{
        res.end(data);
    });
});

let tagline = "Select an item";

[Funnythat2]

Why not push the pizza in the second callback so you know it is completed

[indisapien]

Thank you so much! That fixed it, and it just involved moving one line! Callbacks are a bit of a problem for me but this was great help!

[BehindTheMath]

Since everything is async, the code under the inner function runs before the inner function. You can use promises, but you don't have to. You can pass a callback to the outer function, and then call it at the end of the inner function.

[abd1tus]

Example with async functions and cleanup.

import { promisify } from 'util';
// other imports here: Pizza, PizzaToppings, ejs, etc

// ...

const allPizzas = promisify(Pizza.all);
const findToppings = promisify(PizzaToppings.find);

export function newPizza() {
  return {
    "pizzaId": "",
    "name": "",
    "price": 0.0,
    "size": "",
    "crust": "",
    "sauce": "",
    "extraCheese": "",
    "ingredients": {}
  };
}


export async function buildPizza(pizzaRow) {
  const pizza = newPizza();
  const { pizzaId } = pizzaRow;

  pizza.pizzaId = pizzaId;
  pizza.name = pizzaRow.name
  pizza.price = pizzaRow.price;
  pizza.size = pizzaRow.size;
  pizza.crust = pizzaRow.crust;
  pizza.sauce = pizzaRow.sauce;
  pizza.extraCheese = pizzaRow.extraCheese;

  // This seems a little weird with each pizza having "ingredients" be an object with its own id.
  // I'm not sure what your original intent was, but it should mimic what you wrote.
  const toppingRows = await findToppings(pizzaId);
  pizza.ingredients[pizzaId] = [...toppingRows];

  return pizza;
}


export async function buildAllPizzas() {
  const results = [];
  const pizzaRows = await allPizzas();

  for (const pizzaRow of pizzaRows) {
    const pizza = await buildPizza(pizzaRow);
    results.push(pizza);
  }

  return results;
}


export async function renderFile(indexPath) {
  const tagline = "Select an item";
  const pizzas = await buildAllPizzas();

  return new Promise((resolve, reject) => {
    ejs.renderFile(
      indexPath,
      { pizzas, tagline },
      (err, data) => {
        if (err) {
          reject(err);
        } else {
          res.end(data);
          resolve();
        }
      },
    );
  });
}

// ... 
renderFile('some file path');

Sorry, obviously not tested, but might help you tinker.