Get value based on sub-array unique value

Question

My JSON data looks like this:

{
    "data": [{
            "id": "1",
            "blogTitle": "How to plant a tree?",
            "categories": [{
                "CategoryID": "10",
                "CategoryTitle": "Apple Tree"
            }, {
                "CategoryID": "11",
                "CategoryTitle": "Mango Tree"
            }, {
                "CategoryID": "42",
                "CategoryTitle": "Banana Tree"
            }]
        },
        {
            "id": "2",
            "blogTitle": "How to make Juice?",
            "categories": [{
                "CategoryID": "71",
                "CategoryTitle": "Apple Juice"
            }, {
                "CategoryID": "72",
                "CategoryTitle": "Mango Juice"
            }, {
                "CategoryID": "73",
                "CategoryTitle": "Banana Juice"
            }]

        }
    ]
}

What I want is to get the value of id by passing the value of CategoryID

For example: if I send 10 then I should get 1 in return because "CategoryID": "10" is in the same block with "id": "1"

Each CategoryID is unique resulting in a unique value of id

What did I do?

Closest I came up with was using the array.filter() but I am able to filter id value give the value of id but how do I get the value of id, given CategoryID

Could someone please kindly help me?

Nguyễn Văn Phong · Accepted Answer · 2021-04-09 02:43:01Z

4

You can integrate your data, then use Array#some like this.

const yourObject = {"data":[{"id":"1","blogTitle":"How to plant a tree?","categories":[{"CategoryID":"10","CategoryTitle":"Apple Tree"},{"CategoryID":"11","CategoryTitle":"Mango Tree"},{"CategoryID":"42","CategoryTitle":"Banana Tree"}]},{"id":"2","blogTitle":"How to make Juice?","categories":[{"CategoryID":"71","CategoryTitle":"Apple Juice"},{"CategoryID":"72","CategoryTitle":"Mango Juice"},{"CategoryID":"73","CategoryTitle":"Banana Juice"}]}]};

const find_ID_BasedOn_GivenCategoryId = (categoryId) => {
  for(const item of yourObject.data){
    if(item.categories && item.categories.some(r => r.CategoryID == categoryId))
      return item.id;
  }
  
  return "Not found";
}

console.log(find_ID_BasedOn_GivenCategoryId(11));
console.log(find_ID_BasedOn_GivenCategoryId(71));
console.log(find_ID_BasedOn_GivenCategoryId(999));

Simpler approach: using Array#find

const yourObject = {"data":[{"id":"1","blogTitle":"How to plant a tree?","categories":[{"CategoryID":"10","CategoryTitle":"Apple Tree"},{"CategoryID":"11","CategoryTitle":"Mango Tree"},{"CategoryID":"42","CategoryTitle":"Banana Tree"}]},{"id":"2","blogTitle":"How to make Juice?","categories":[{"CategoryID":"71","CategoryTitle":"Apple Juice"},{"CategoryID":"72","CategoryTitle":"Mango Juice"},{"CategoryID":"73","CategoryTitle":"Banana Juice"}]}]};

const find_ID_BasedOn_GivenCategoryId = (categoryId) => {
  const result = yourObject.data.find(item => 
                item.categories && item.categories.some(r => r.CategoryID == categoryId));
  
 return result ? result.id : "Not found"; 
}

console.log(find_ID_BasedOn_GivenCategoryId(11));
console.log(find_ID_BasedOn_GivenCategoryId(71));
console.log(find_ID_BasedOn_GivenCategoryId(999));

edited Apr 9, 2021 at 2:43

answered Apr 9, 2021 at 1:22

Nguyễn Văn Phong

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4 Comments

floss Over a year ago

thank you for composing the answer. I am getting this error: Cannot read property 'some' of undefined

Nguyễn Văn Phong Over a year ago

Updated my answer, pls take a look at it @floss

floss Over a year ago

thank you! it works. what if the categoryId does not exists?

Nguyễn Văn Phong Over a year ago

You can return Not found like the updated answer.

marcos · Accepted Answer · 2021-04-09 01:24:30Z

1

You can use find with a combination of some for checking the categoryID that you want, for example:

const data = {
    "data": [{
            "id": "1",
            "blogTitle": "How to plant a tree?",
            "categories": [{
                "CategoryID": "10",
                "CategoryTitle": "Apple Tree"
            }, {
                "CategoryID": "11",
                "CategoryTitle": "Mango Tree"
            }, {
                "CategoryID": "42",
                "CategoryTitle": "Banana Tree"
            }]
        },
        {
            "id": "2",
            "blogTitle": "How to make Juice?",
            "categories": [{
                "CategoryID": "71",
                "CategoryTitle": "Apple Juice"
            }, {
                "CategoryID": "72",
                "CategoryTitle": "Mango Juice"
            }, {
                "CategoryID": "73",
                "CategoryTitle": "Banana Juice"
            }]

        }
    ]
};


const findId = (categoryID, { data }) => {
    const foundItem = data.find(({ categories }) => 
      categories.some(({ CategoryID }) => CategoryID == categoryID)
    );
    return foundItem ? foundItem.id : null;
}

console.log(findId(71, data))

answered Apr 9, 2021 at 1:24

marcos

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1 Comment

Nguyễn Văn Phong Over a year ago

You will get an error like Cannot read property 'some' of undefined when categories is undefine or null. Check my answer above in more details :)

Yu Miao · Accepted Answer · 2021-04-09 01:39:04Z

1

find + some

var data = [
  {
    id: "1",
    blogTitle: "How to plant a tree?",
    categories: [
      {
        CategoryID: "10",
        CategoryTitle: "Apple Tree"
      },
      {
        CategoryID: "11",
        CategoryTitle: "Mango Tree"
      },
      {
        CategoryID: "42",
        CategoryTitle: "Banana Tree"
      }
    ]
  },
  {
    id: "2",
    blogTitle: "How to make Juice?",
    categories: [
      {
        CategoryID: "71",
        CategoryTitle: "Apple Juice"
      },
      {
        CategoryID: "72",
        CategoryTitle: "Mango Juice"
      },
      {
        CategoryID: "73",
        CategoryTitle: "Banana Juice"
      }
    ]
  }
];

const findId = (id) => {
  return data?.find((item) =>
    item?.categories?.some((i) => i?.CategoryID === id)
  )?.id;
};


console.log(findId("10")); //1

edited Apr 9, 2021 at 1:39

answered Apr 9, 2021 at 1:36

Yu Miao

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2 Comments

Nguyễn Văn Phong Over a year ago

You will get an error at this like .id; when not found.

Yu Miao Over a year ago

fix error: add optional chaining. It will return undefined, when not fond.

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