TypeScript 食品科學：具備型別安全的營養分析

            
interface Food {
  name: string;
  calories: number;
  protein: number;
  fat: number;
  carbohydrates: number;
  sodium?: number; // Optional property
  vitamins?: Record; // Optional object for vitamins
}

const apple: Food = {
  name: "Apple",
  calories: 95,
  protein: 0.3,
  fat: 0.2,
  carbohydrates: 25,
  vitamins: {
    "Vitamin C": 0.05,
    "Vitamin A": 0.03,
  },
};

function printFoodDetails(food: Food): void {
  console.log(`Food: ${food.name}`);
  console.log(`Calories: ${food.calories}`);
  console.log(`Protein: ${food.protein}g`);
  console.log(`Fat: ${food.fat}g`);
  console.log(`Carbohydrates: ${food.carbohydrates}g`);
  if (food.sodium) {
    console.log(`Sodium: ${food.sodium}mg`);
  }
  if (food.vitamins) {
    console.log("Vitamins:");
    for (const vitamin in food.vitamins) {
      console.log(`  ${vitamin}: ${food.vitamins[vitamin]}`);
    }
  }
}

printFoodDetails(apple);

            

              
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interface RecipeIngredient {
  food: Food;
  quantity: number;
  unit: string; // e.g., "g", "oz", "cup"
}

function calculateTotalCalories(ingredients: RecipeIngredient[]): number {
  let totalCalories = 0;
  for (const ingredient of ingredients) {
    totalCalories += ingredient.food.calories * ingredient.quantity;
  }
  return totalCalories;
}

const recipeIngredients: RecipeIngredient[] = [
  {
    food: apple,
    quantity: 2, // Two apples
    unit: "serving",
  },
  {
    food: {
      name: "Banana",
      calories: 105,
      protein: 1.3,
      fat: 0.4,
      carbohydrates: 27,
    },
    quantity: 1,
    unit: "serving",
  },
];

const totalCalories = calculateTotalCalories(recipeIngredients);
console.log(`Total Calories: ${totalCalories}`); // Output: Total Calories: 295

            

              
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interface ApiResponse {
  success: boolean;
  data?: Food;
  error?: string;
}

async function fetchFoodData(foodName: string): Promise {
  // Simulate fetching data from an API
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      const mockData: any = { // any type is used because the api response is not type-safe
        name: foodName,
        calories: Math.floor(Math.random() * 200),
        protein: Math.random() * 5,
        fat: Math.random() * 10,
        carbohydrates: Math.random() * 30,
      };

      const isValidFood = (data: any): data is Food => {
          return (typeof data.name === 'string' &&
                  typeof data.calories === 'number' &&
                  typeof data.protein === 'number' &&
                  typeof data.fat === 'number' &&
                  typeof data.carbohydrates === 'number');
      };

      if (isValidFood(mockData)) {
          resolve({ success: true, data: mockData });
      } else {
          resolve({ success: false, error: "Invalid food data" });
      }
    }, 500);
  });
}

fetchFoodData("Mango")
  .then((response) => {
    if (response.success && response.data) {
      console.log("Food data:", response.data);
    } else {
      console.error("Error fetching food data:", response.error);
    }
  })
  .catch((error) => {
    console.error("An unexpected error occurred:", error);
  });

            

              
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function calculateAverage(foods: T[], nutrient: K): number {
  let sum = 0;
  let count = 0;

  for (const food of foods) {
    if (typeof food[nutrient] === 'number') { // Only process if the nutrient is a number
      sum += food[nutrient] as number; // Type assertion to number
      count++;
    }
  }

  return count > 0 ? sum / count : 0;
}

const foods: Food[] = [
  { name: "Apple", calories: 95, protein: 0.3, fat: 0.2, carbohydrates: 25 },
  { name: "Banana", calories: 105, protein: 1.3, fat: 0.4, carbohydrates: 27 },
  { name: "Orange", calories: 62, protein: 1.2, fat: 0.2, carbohydrates: 15 },
];

const averageCalories = calculateAverage(foods, "calories");
console.log(`Average Calories: ${averageCalories}`);

const averageProtein = calculateAverage(foods, "protein");
console.log(`Average Protein: ${averageProtein}`);

// Demonstrate with optional property - this will return 0 because Food does not have 'sodium' property defined directly in all objects.
const averageSodium = calculateAverage(foods, "sodium");
console.log(`Average Sodium: ${averageSodium}`);

            

              
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