Food details and portions

Logging a food or predicting glucose takes a FoodSelection: a food ID, a serving ID, and a quantity. Build one in three steps:

1. Find the food with foods.search, foods.autocomplete, or foods.lookupBarcode.

2. Fetch the full food with foods.get. Search and autocomplete results can carry less detail.

3. Pick one of its servings and a quantity greater than zero.

import type { FoodSelection, JanuaryClient } from '@januaryai/react-native';

export async function selectFood(
  january: JanuaryClient,
  query: string,
  quantity = 1
): Promise<FoodSelection | undefined> {
  const { items } = await january.foods.search({ query });
  const match = items[0]; // in your UI, the result the user picked
  if (!match) return undefined;

  const food = await january.foods.get({ foodId: match.id });
  const serving = food.servings.find((s) => s.isPrimary) ?? food.servings[0];
  if (!serving?.id) return undefined;

  return { id: food.id, serving: { id: serving.id, quantity } };
}

quantity is how many of that serving were eaten: for a "6 oz" serving, 1 is 6 oz and 0.5 is 3 oz. Take serving IDs from food.servings as returned; don't build them from labels.

A food analysis detection already carries a serving and a quantity, so it can be logged without these steps.