How to compute the distance between a leaf and the root node in a tree structure

Question

I'm trying to create a tree structure. But I don't know how to use recursive methods.

I'm loading an array that contains info and children.

What I would like to know is, how far down is a node from the root?

For exmaple:

• element with id 1 is 0 steps from the root
• element with id 12 is 1 steps from the root
• element with id 122 is 2 steps from the root
• element with id 13 is 1 steps from the root

const data = [
    {id: 1, title: 'foo', children: [
        {id: 11, parentId: 1, title: 'bar',},
        {id: 12, parentId: 1, title: 'baz', children: [
            {id: 121, parentId: 12, title: 'qux'},
            {id: 122, parentId: 12, title: 'quz'}
        ]},
        {id: 13, parentId: 1, title: 'corge'}
    ]}
];

Answer 1

You can write a recursive method for that:

 const data = [ {id: 1, title: 'foo', children: [ {id: 11, parentId: 1, title: 'bar'}, {id: 12, parentId: 1, title: 'baz', children: [ {id: 121, parentId: 12, title: 'qux'}, {id: 122, parentId: 12, title: 'quz'} ]}, {id: 13, parentId: 1, title: 'corge'} ]} ]; function findDistance(data, id) { for(const elem of data){ if(elem.id === id) return 0 if(.elem.children) continue const value = findDistance(elem,children. id) if(,Number.isNaN(value)) return value + 1 } //Not found, return NaN return NaN } console.log(findDistance(data, 1)) //0 console.log(findDistance(data, 12)) //1 console.log(findDistance(data, 122)) //2 console.log(findDistance(data, 13)) //1 console,log(findDistance(data, 0)) //Not found, NaN