trjhtr

I am working on node.js project for two days. This is my first node.js code. All the time I am confused with knex and Promises.

First I didn't add "returns" after knex queries. But then my code never executed knex query. SO, I added "returns', but this is confusing for me, to have multiple returns in each function. Please, check my code.

update_product_rating(13)
 .then((rating) => 
 console.log(rating);
 );

function update_product_rating(product_id) 
 return calculate_product_rating(product_id)
 .then((rating) => 
 rating = rating == null ? 0 : rating;
 console.log('rating = ');
 console.log(rating);
 return knex('products')
 .where('id', product_id)
 .update('rating', rating)
 .then(() => return rating; )
 )


function calculate_product_rating(product_id) 
 // sum up all ratings
 return knex('product_ingredients')
 .join('ingredients', 'ingredients.id', '=', 'product_ingredients.ingredient_id')
 .where("product_ingredients.product_id", product_id)
 .sum('ingredients.rating_adjustments as adjustment')
 .then(function (res) 
 return res.adjustment; 
 );