TS-question 2021-05-18

// This mirrors the SQL table (ID and timestamps generated automatically)
interface Product {
  id: number;
  name: string;
  comment?: string;
  category: number;
  created_at: string;
  updated_at: string;
}

export async function selectAll(): Promise<Product[]> {
  const rows = await knex<Product>("products").select();
  return rows;
}

export async function selectByID(id: number): Promise<Product> {
  const rows = await knex<Product>("products").select().where("id", id);
  return rows[0];
}

export async function selectByName(
  name: string,
  strategy: string
): Promise<Product[]> {
  const query = knex<Product>("products").select();

  switch (strategy) {
    case "exact":
      query.where("name", name);
      break;
    case "contains":
      query.where("name", "like", `%${name}%`);
      break;
    default:
      query.where("name", "like", `${name}%`);
  }

  query.then((rows: Product[]) => rows);
  return query;
}

export async function insert(
  name: string,
  category: number,
  comment: string
): Promise<Product> {
  await knex<Product>("products").insert({
    name: name,
    category: category,
    comment: comment,
  });
  const newProduct = await selectByName(name, "exact");
  if (newProduct.length != 1) {
    throw new Error("Error when inserting new product");
  } else {
    return newProduct[0];
  }
}

export async function update(product: Product): Promise<Product> {
  await knex<Product>("products").where("id", product.id).update({
    name: product.name,
    category: product.category,
    comment: product.comment,
    updated_at: knex.fn.now(),
  });
  return await selectByID(product.id);
}

export async function remove(id: number): Promise<{ message: string }> {
  await knex<Product>("products").where("id", id).del();
  const message = ResponseMessages.DeleteOK.message;
  return { message };
}