Find object and parent object in repeatedly nested array

Question

How to find an object and parent object in repeatedly nested array of unknown size? Using lodash or native javascript.

Array might be something like this:

var modules = [{
    name: 'Module1',
    submodules: [{
        name: 'Submodule1',
        id: 1,
        submodules: [{
          name: 'Submodule11',
          id: 1,
          submodules: []
        }, {
          name: 'Submodule12',
          id: 2,
          submodules: [{
            name: 'Submodule121',
            id: 1,
            submodules: []
          }, {
            name: 'Submodule122',
            id: 2,
            submodules: []
          }]
        }]
      },
      {
        name: 'Submodule2',
        id: 2,
        submodules: []
      }
    ]
  },
  {
    name: 'Module2',
    submodules: [{
      name: 'Submodule1',
      id: 3,
      submodules: []
    }, {
      name: 'Submodule2',
      id: 4,
      submodules: []
    }]
  }
];

And let's say all the 'name' properties in array are unique.

And I want to find:

name: 'Submodule122'

I was using this function for finding parent object but it works only on first level of array:

_.find(this.modules , function(item) {
            return _.some(item.submodules, { name: 'Submodule122'});

And this to find actual object, but it also works only on first level of array:

_(this.modules)
            .thru(function (coll) {
                return _.union(coll, _.map(coll, 'submodules'));
            })
            .flatten()
            .find({ name: 'Submodule122'})

Nina Scholz · Accepted Answer · 2018-07-09 09:42:11Z

You could take an iterative and recursive approach by keeping the actual object as parent.

function find(name, array, parent) {
    var result;
    array.some(object =>
        object.name === name && (result = { object, parent }) || 
        (result = find(name, object.submodules, object))
    );
    return result;
}

var modules = [{ name: 'Module1', submodules: [{ name: 'Submodule1', id: 1, submodules: [{ name: 'Submodule11', id: 1, submodules: [] }, { name: 'Submodule12', id: 2, submodules: [{ name: 'Submodule121', id: 1, submodules: [] }, { name: 'Submodule122', id: 2, submodules: [] }] }, { name: 'Submodule2', id: 2, submodules: [] }] }, { name: 'Module2', submodules: [{ name: 'Submodule1', id: 3, submodules: [] }, { name: 'Submodule2', id: 4, submodules: [] }] }] }];

console.log(find('Submodule122', modules));

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Karan · Accepted Answer · 2018-07-09 09:56:52Z

var modules = [{
    name: 'Module1',
    submodules: [{
        name: 'Submodule1',
        id: 1,
        submodules: [{
          name: 'Submodule11',
          id: 1,
          submodules: []
        }, {
          name: 'Submodule12',
          id: 2,
          submodules: [{
            name: 'Submodule121',
            id: 1,
            submodules: []
          }, {
            name: 'Submodule122',
            id: 2,
            submodules: []
          }]
        }]
      },
      {
        name: 'Submodule2',
        id: 2,
        submodules: []
      }
    ]
  },
  {
    name: 'Module2',
    submodules: [{
      name: 'Submodule1',
      id: 3,
      submodules: []
    }, {
      name: 'Submodule2',
      id: 4,
      submodules: []
    }]
  }
];

var findByName = (name, module, parent, item) => {
  parent.push(...module.filter(x => Array.isArray(x.submodules) && x.submodules.some(y => y.name == name)));
  item.push(...module.filter(y => y.name == name));

  module.forEach(x => {
    if (Array.isArray(x.submodules) && x.submodules.length > 0) {
      findByName(name, x.submodules, parent, item);
    }
  });

}

var parents = [], items = [];
findByName('Submodule12', modules, parents, items);
console.log(parents);
console.log(items);

vincent · Accepted Answer · 2021-01-19 01:38:24Z

Not exactly what was asked for, but I thought still worthwhile sharing. We now use object-scan for all our data processing tasks and it's really powerful once you've wrapped your head around it. Here is how you'd answer your questions

Note that this returns all parents, but it's easy enough to pick the ones that you want.

// const objectScan = require('object-scan');

const search = (name, data) => objectScan(['**.name'], {
  rtn: 'parents',
  abort: true,
  filterFn: ({ value }) => value === name
})(data);

const modules = [{ name: 'Module1', submodules: [{ name: 'Submodule1', id: 1, submodules: [{ name: 'Submodule11', id: 1, submodules: [] }, { name: 'Submodule12', id: 2, submodules: [{ name: 'Submodule121', id: 1, submodules: [] }, { name: 'Submodule122', id: 2, submodules: [] }] }] }, { name: 'Submodule2', id: 2, submodules: [] }] }, { name: 'Module2', submodules: [{ name: 'Submodule1', id: 3, submodules: [] }, { name: 'Submodule2', id: 4, submodules: [] }] }];

console.log(search('Submodule122', modules));
/* =>
[ { name: 'Submodule122', id: 2, submodules: [] },
  [ { name: 'Submodule121', id: 1, submodules: [] },
    { name: 'Submodule122', id: 2, submodules: [] } ],
  { name: 'Submodule12',
    id: 2,
    submodules:
     [ { name: 'Submodule121', id: 1, submodules: [] },
       { name: 'Submodule122', id: 2, submodules: [] } ] },
  [ { name: 'Submodule11', id: 1, submodules: [] },
    { name: 'Submodule12',
      id: 2,
      submodules:
       [ { name: 'Submodule121', id: 1, submodules: [] },
         { name: 'Submodule122', id: 2, submodules: [] } ] } ],
  { name: 'Submodule1',
    id: 1,
    submodules:
     [ { name: 'Submodule11', id: 1, submodules: [] },
       { name: 'Submodule12',
         id: 2,
         submodules:
          [ { name: 'Submodule121', id: 1, submodules: [] },
            { name: 'Submodule122', id: 2, submodules: [] } ] } ] },
  [ { name: 'Submodule1',
      id: 1,
      submodules:
       [ { name: 'Submodule11', id: 1, submodules: [] },
         { name: 'Submodule12',
           id: 2,
           submodules:
            [ { name: 'Submodule121', id: 1, submodules: [] },
              { name: 'Submodule122', id: 2, submodules: [] } ] } ] },
    { name: 'Submodule2', id: 2, submodules: [] } ],
  { name: 'Module1',
    submodules:
     [ { name: 'Submodule1',
         id: 1,
         submodules:
          [ { name: 'Submodule11', id: 1, submodules: [] },
            { name: 'Submodule12',
              id: 2,
              submodules:
               [ { name: 'Submodule121', id: 1, submodules: [] },
                 { name: 'Submodule122', id: 2, submodules: [] } ] } ] },
       { name: 'Submodule2', id: 2, submodules: [] } ] },
  [ { name: 'Module1',
      submodules:
       [ { name: 'Submodule1',
           id: 1,
           submodules:
            [ { name: 'Submodule11', id: 1, submodules: [] },
              { name: 'Submodule12',
                id: 2,
                submodules:
                 [ { name: 'Submodule121', id: 1, submodules: [] },
                   { name: 'Submodule122', id: 2, submodules: [] } ] } ] },
         { name: 'Submodule2', id: 2, submodules: [] } ] },
    { name: 'Module2',
      submodules:
       [ { name: 'Submodule1', id: 3, submodules: [] },
         { name: 'Submodule2', id: 4, submodules: [] } ] } ] ]
 */

console.log(search('unknown', modules));
// => undefined

.as-console-wrapper {max-height: 100% !important; top: 0}

<script src="https://bundle.run/[email protected]"></script>

Disclaimer: I'm the author of object-scan

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