Find all related object in array and sort with ID-CodePudding

I have category list with ID and parentId. Each category parentId is other category id. If I have some selectedCategory, for example: 10 (which means category with id: 10), I want to create a new array where the last object will be category with id: 10 - { title: 'category 10', id: 10, parentId: 6}, after that category with id: 6 (because of previous object parentId) and so on, until the category parentId is 0.

           let arr = [
                  { title: 'category 1', id: 1, parentId: 0},
                  { title: 'category 2', id: 2, parentId: 1},
                  { title: 'category 3', id: 3, parentId: 4},
                  { title: 'category 4', id: 4, parentId: 2},
                  { title: 'category 5', id: 5, parentId: 3},
                  { title: 'category 6', id: 6, parentId: 2},
                  { title: 'category 7', id: 7, parentId: 5},
                  { title: 'category 8', id: 8, parentId: 0},
                  { title: 'category 9', id: 9, parentId: 0},
                  { title: 'category 10', id: 10, parentId: 6},
            ]

So, in this case the result Array should be:

        let resultArr = [
              { title: 'category 10', id: 10, parentId: 6},
              { title: 'category 6', id: 6, parentId: 2},
              { title: 'category 2', id: 2, parentId: 1},
              { title: 'category 1', id: 1, parentId: 0},
        ]

CodePudding user response：

You can do something like this

const arr = [{ title: "category 1", id: 1, parentId: 0 }, { title: "category 2", id: 2, parentId: 1 }, { title: "category 3", id: 3, parentId: 4 }, { title: "category 4", id: 4, parentId: 2 }, { title: "category 5", id: 5, parentId: 3 }, { title: "category 6", id: 6, parentId: 2 }, { title: "category 7", id: 7, parentId: 5 }, { title: "category 8", id: 8, parentId: 0 }, { title: "category 9", id: 9, parentId: 0 }, { title: "category 10", id: 10, parentId: 6 }];

const idMap = arr.reduce((acc, curr) => {
    acc[curr.id] = curr;
    return acc;
}, {});

const getParents = (id) => {
    const result = [];

    let current = idMap[id];
    while (current) {
        result.push(current);
        current = idMap[current.parentId];
    }

    return result;
};

console.log(getParents(10));

CodePudding user response：

you can easily do this using a generator function.

const log = console.log;

let arr = [
  { title: 'category 1', id: 1, parentId: 0},
  { title: 'category 2', id: 2, parentId: 1},
  { title: 'category 3', id: 3, parentId: 4},
  { title: 'category 4', id: 4, parentId: 2},
  { title: 'category 5', id: 5, parentId: 3},
  { title: 'category 6', id: 6, parentId: 2},
  { title: 'category 7', id: 7, parentId: 5},
  { title: 'category 8', id: 8, parentId: 0},
  { title: 'category 9', id: 9, parentId: 0},
  { title: 'category 10', id: 10, parentId: 6},
]

function* getCategories(arr, id) {
 let category = arr.find(elm => elm.id === id)
 do {
   yield category
   category = arr.find(elm => elm.id === category.parentId)
 } while(category)
}

const categories = getCategories(arr, 10)
const resultArr = [...categories]

log(resultArr)

checkout generators:

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Generator