Javascript 如何循环类别以获取子类别并在其中创建嵌套的子类别数组？

我有以下类别对象数组，其中包含类别Id、类别名称和子类别

{
"categories":[
{
"id_product_cat":1,
"prod_category_name":"food",
"subcategory":"Pizza"
},
{
"id_product_cat":1,
"prod_category_name":"food",
"subcategory":"Burger"
},
{
"id_product_cat":1,
"prod_category_name":"food",
"subcategory":"Chicken"
},
{
"id_product_cat":1,
"prod_category_name":"food",
"subcategory":"Sandwiches"
},
{
"id_product_cat":2,
"prod_category_name":"drinks ",
"subcategory":"Alcoholic Drinks"
},
{
"id_product_cat":2,
"prod_category_name":"drinks ",
"subcategory":"Non-alcoholic Drinks"
},
{
"id_product_cat":2,
"prod_category_name":"drinks ",
"subcategory":"Coffee"
},
{
"id_product_cat":1,
"prod_category_name":"food",
"subcategory":"Test"
}
]
}

我想循环遍历Categories数组，并返回一个新数组，该数组具有Category Id、Category name和每个不同类别的嵌套子类别数组。我期望的结果是：

{
"categories":[
{
"id_product_cat":1,
"prod_category_name":"food",
"subcategories":["Pizza","Burger","Chicken","Sandwiches"]
},
{
"id_product_cat":2,
"prod_category_name":"drinks ",
"subcategories":["Alcoholic Drinks","Non-alcoholic Drinks","Coffee"]
}]
}

---

要做到这一点，你需要把问题分成两部分

首先，您需要将每个类别分组在一起。只需使用reduce即可。（为什么要使用reduce？以避免循环到循环，如此复杂）

一旦你这样做了，你将有你的类别正确分组

最后，您需要正确格式化输出，为此，只需在groupedCategories对象上使用循环即可，例如：

---

我希望这些代码示例能够帮助您找到实现目标的方法

您可以使用

Array.reduce（）

收集所有类别

let data = {
"categories":[
{
"id_product_cat":1,
"prod_category_name":"food",
"subcategory":"Pizza"
},
{
"id_product_cat":1,
"prod_category_name":"food",
"subcategory":"Burger"
},
{
"id_product_cat":1,
"prod_category_name":"food",
"subcategory":"Chicken"
},
{
"id_product_cat":1,
"prod_category_name":"food",
"subcategory":"Sandwiches"
},
{
"id_product_cat":2,
"prod_category_name":"drinks ",
"subcategory":"Alcoholic Drinks"
},
{
"id_product_cat":2,
"prod_category_name":"drinks ",
"subcategory":"Non-alcoholic Drinks"
},
{
"id_product_cat":2,
"prod_category_name":"drinks ",
"subcategory":"Coffee"
},
{
"id_product_cat":1,
"prod_category_name":"food",
"subcategory":"Test"
}
]
}

let existingCategory = acc.find((checkCategory)=>{ return category.id_product_cat === checkCategory.id_product_cat });
if(existingCategory){// checking for existing category
    existingCategory.subcategory.push(category.subcategory);
}else{
    category.subcategory = [category.subcategory];
    acc.push(category);
}
return acc;
},[]);
console.log(categories);

const output = {
  categories: Object.keys(groupedCategories).map(categoryId => ({
    id_product_cat: categoryId,
    prod_category_name: groupedCategories[categoryId].prod_category_name,
    subcategories: groupedCategories[categoryId].subCategories,
  }))
};

let data = {
"categories":[
{
"id_product_cat":1,
"prod_category_name":"food",
"subcategory":"Pizza"
},
{
"id_product_cat":1,
"prod_category_name":"food",
"subcategory":"Burger"
},
{
"id_product_cat":1,
"prod_category_name":"food",
"subcategory":"Chicken"
},
{
"id_product_cat":1,
"prod_category_name":"food",
"subcategory":"Sandwiches"
},
{
"id_product_cat":2,
"prod_category_name":"drinks ",
"subcategory":"Alcoholic Drinks"
},
{
"id_product_cat":2,
"prod_category_name":"drinks ",
"subcategory":"Non-alcoholic Drinks"
},
{
"id_product_cat":2,
"prod_category_name":"drinks ",
"subcategory":"Coffee"
},
{
"id_product_cat":1,
"prod_category_name":"food",
"subcategory":"Test"
}
]
}

let existingCategory = acc.find((checkCategory)=>{ return category.id_product_cat === checkCategory.id_product_cat });
if(existingCategory){// checking for existing category
    existingCategory.subcategory.push(category.subcategory);
}else{
    category.subcategory = [category.subcategory];
    acc.push(category);
}
return acc;
},[]);
console.log(categories);