CODEWITHSUNDEEP
javascriptlodash
Mistre83
Mistre83

Reputation: 2827

Lodash - Find deep in array of object

I have an array of an object like this

[
    {
        'a': 10,
        elements: [
            {
                'prop': 'foo',
                'val': 10
            },
            {
                'prop': 'bar',
                'val': 25
            },
            {
                'prop': 'test',
                'val': 51
            }
        ]
    },
    {
        'b': 50,
        elements: [
            {
                'prop': 'foo',
                'val': 30
            },
            {
                'prop': 'bar',
                'val': 15
            },
            {
                'prop': 'test',
                'val': 60
            }
        ]
    },
]

What I need is sum the property Val when prop is foo. So, I have to search through elements and get all objects where prop is foo. With this objects, I should sum the val property.

I tried to use many combinations of _.find, _.pick and so on, but I don't get the right result. Can someone help me?

Upvotes: 15

Views: 60164

Answers (6)

Yuri Gor
Yuri Gor

Reputation: 1463

Disclosure: I am the author of that library

You can use _.eachDeep method from deepdash:

let sum = 0;
_.eachDeep(obj, (value, key, parent) => {
  sum += (key == 'prop' && value == 'foo' && parent.val) || 0;
});

here is an example for your case

Upvotes: 1

Markov
Markov

Reputation: 150

here the solution that worked for me if anyone needs it. but my case was a bit different, I needed to find an array that matches the id.

here a flow function which is not really nesesary but it does make the code easier to read

const flow = functions => data =>
    functions.reduce((value, func) => func(value), data);

   const arr = [
        {
            'a': 10,
            elements: [
                {
                    'prop': 'foo',
                    'val': 10
                },
                {
                    'prop': 'bar',
                    'val': 25
                },
                {
                    'prop': 'test',
                    'val': 51
                }
            ]
        },
        {
            'b': 50,
            elements: [
                {
                    'prop': 'foo',
                    'val': 30
                },
                {
                    'prop': 'bar',
                    'val': 15
                },
                {
                    'prop': 'test',
                    'val': 60
                }
            ]
        },
    ]

    const result= _.flow([
        data => _.map(data, 'elements'), // get all elements from the array 
        data => _.flatten(data), // create a singler array 
        data => _.find(data, { val: 65 }) // find the needed value in array 
        // you can keep on adding logic here depending on your need
    ])(arr); // the inital array

if you dont want to use the flow function it can also be done like that I think I didnt test the code but it should work

const results = _.find(_.flatten(_.map(arr, 'elements')), { val: 65 });

Upvotes: 0

Ahsan Babar
Ahsan Babar

Reputation: 51

Here's a one liner solution to this problem:

const _ = require('lodash')

let deepFind = (JSONArray, keyPath, keyValue) => _.find(JSONArray, _.matchesProperty(keyPath, keyValue))

let JSONArray = [{a:1, b:2, c:{d: "cd"}}, {a:3, b:4, c:{d: "ef"}}, {a:3, b:4, c:[{d: "ef"}]} ]

console.log(deepFind(JSONArray, "c.d", "cd"))
// {a:1, b:2, c:{d: "cd"}}

console.log(deepFind(JSONArray, "b", 4)) 
//{a:3, b:4, c:{d: "ef"}}

console.log(deepFind(JSONArray, ['c', 'd'], "cd"))
//{a:1, b:2, c:{d: "cd"}}

console.log(deepFind(JSONArray, 'c[0].d' /* OR ['c', '0', 'd']*/, "ef"))
//{a:1, b:2, c:{d: "cd"}}

Upvotes: 5

dominik791
dominik791

Reputation: 752

I've created library that you can use: https://github.com/dominik791/obj-traverse

findAll() method should solve your problem. The first parameter is a root object, not array, so you should create it at first:

var rootObj = {
  name: 'rootObject',
  elements: [
    {
      'a': 10,
       elements: [ ... ]
    },
    {
       'b': 50,
       elements: [ ... ]
    }
  ]
};

Then use findAll() method:

var matchingObjects = findAll( rootObj, 'elements', { 'prop': 'foo' } );

matchingObjects variable stores all objects with prop equal to foo. And at the end calculate your sum:

var sum = 0;
matchingObjects.forEach(function(obj) {
  sum += obj.val;
});

Upvotes: 5

Gruff Bunny
Gruff Bunny

Reputation: 27976

Here's a solution that flattens the elements and then filters the result to get the required elements before summing the val property:

var result = _.chain(data)
    .map('elements')               // pluck all elements from data
    .flatten()                     // flatten the elements into a single array
    .filter({prop: 'foo'})         // exatract elements with a prop of 'foo'
    .sumBy('val')                  // sum all the val properties
    .value()

Chaining is a way of applying a sequence of operations to some data before returning a value. The above example uses explicit chaining but could be (maybe should be) written using implicit chaining:

var result = _(data)
    .map('elements')
    .flatten()
    .filter({prop: 'foo'})
    .sumBy('val');

Upvotes: 28

Suchit kumar
Suchit kumar

Reputation: 11859

You can loop through the data and get the sum.Try this:

var arr=[
     {
         'a': 10,
         elements: [
             {
                 'prop': 'foo',
                 'val': 10
             },
             {
                 'prop': 'bar',
                 'val': 25
             },
             {
                 'prop': 'test',
                 'val': 51
             }
         ]
     },
     {
         'b': 50,
         elements: [
             {
                 'prop': 'foo',
                 'val': 30
             },
             {
                 'prop': 'bar',
                 'val': 15
             },
             {
                 'prop': 'test',
                 'val': 60
             }
         ]
     }
 ];
 var sum=0;
 for(x in arr){
 for(i in arr[x]['elements']){
   if(arr[x]['elements'][i]['prop'] == 'foo'){
	   sum=sum+arr[x]['elements'][i]['val'];
   }
 }

 }

 console.log(sum);

USING FILTER:

var arr=[
     {
         'a': 10,
         elements: [
             {
                 'prop': 'foo',
                 'val': 10
             },
             {
                 'prop': 'bar',
                 'val': 25
             },
             {
                 'prop': 'test',
                 'val': 51
             }
         ]
     },
     {
         'b': 50,
         elements: [
             {
                 'prop': 'foo',
                 'val': 30
             },
             {
                 'prop': 'bar',
                 'val': 15
             },
             {
                 'prop': 'test',
                 'val': 60
             }
         ]
     }
 ];
 var sum=0;

arr.filter(function (person) { 
  person['elements'].filter(function(data){
  if (data.prop == "foo"){
    sum=sum+data.val;
  }
  });
  });
           
           console.log(sum);

Upvotes: 0

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