Transform a nested object using lodash

Question

Input:

const a =  {
            "8": [{
                "strategy": 123,
                "id": 1,
                "config": {
                    "global_dag_conf": {
                        "algo_v2_conf": {
                            "features_to_combine": [],
                            "segments": [],
                            "force_performance": false,
                            "min_bid": 0,
                            "max_bid": 13
                        }
                    }
                }
            }],
            "13": [{
                "strategy": 456,
                "id": 2,
                "config": {
                    "global_dag_conf": {
                        "algo_v2_conf": {
                            "ivr_measured": []
                        }
                    }
                }
            }]

        }

Output:

{
   "8": [
      {
         "global_dag_conf": {
            "algo_v2_conf": {
               "features_to_combine": [],
               "segments": [],
               "force_performance": false,
               "min_bid": 0,
               "max_bid": 13
            }
         },
         "algo_id": 1
      }
   ],
   "13": [
      {
         "global_dag_conf": {
            "algo_v2_conf": {
               "ivr_measured": []
            }
         },
         "algo_id": 2
      }
   ]
}

I tried below solution which works fine but need to know if is there any better way to do this using lodash and JS.

result = _.map(_.keys(addtionalAlgos), (algoType) => {
    addtionalAlgos[algoType] = _.map(addtionalAlgos[algoType], v => _.assign(v.config, { algo_id: v.id }));
    return addtionalAlgos;
  })[0]

What is the relation between input & output?

brk
– brk

2019-03-23 13:56:12 +00:00
Commented Mar 23, 2019 at 13:56 — brk
– brk, Commented Mar 23, 2019 at 13:56

adiga · Accepted Answer · 2019-03-23 14:12:09Z

1

Here's a solution without using lodash:

Use Object.entries() to get an array of key-value pairs
Create a new object by using reduce over the array
Use map to create a new array of objects.
Destructure each object to get id and config. Spread the config variable to remove one level of nesting

const input = {"8":[{"strategy":123,"id":1,"config":{"global_dag_conf":{"algo_v2_conf":{"features_to_combine":[],"segments":[],"force_performance":false,"min_bid":0,"max_bid":13}}}}],"13":[{"strategy":456,"id":2,"config":{"global_dag_conf":{"algo_v2_conf":{"ivr_measured":[]}}}}]}

const output = 

Object.entries(input)
      .reduce((r, [key, value]) => {
          r[key] = value.map(({ id, config }) => ({ algo_id: id, ...config }));
          return r;
      }, {})
      
console.log(output)

edited Mar 23, 2019 at 14:12

answered Mar 23, 2019 at 14:04

adiga

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Comments

Ori Drori · Accepted Answer · 2019-03-23 14:26:36Z

1

Use _.mapValues() to iterate the keys, and Array.map() with object destructuring and spread syntax to reformat the object:

const data = {"8":[{"strategy":123,"id":1,"config":{"global_dag_conf":{"algo_v2_conf":{"features_to_combine":[],"segments":[],"force_performance":false,"min_bid":0,"max_bid":13}}}}],"13":[{"strategy":456,"id":2,"config":{"global_dag_conf":{"algo_v2_conf":{"ivr_measured":[]}}}}]}

const result = _.mapValues(data, 
  arr => arr.map(({ id: algo_id, config }) => 
    ({ algo_id, ...config })
))

console.log(result)

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.js"></script>

edited Mar 23, 2019 at 14:26

answered Mar 23, 2019 at 13:59

Ori Drori

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Comments

User863 · Accepted Answer · 2019-03-23 14:58:29Z

1

A pure Lodash solution using mapValues, map and assign methods

let data = {"8":[{"strategy":123,"id":1,"config":{"global_dag_conf":{"algo_v2_conf":{"features_to_combine":[],"segments":[],"force_performance":false,"min_bid":0,"max_bid":13}}}}],"13":[{"strategy":456,"id":2,"config":{"global_dag_conf":{"algo_v2_conf":{"ivr_measured":[]}}}}]};

let res = _.mapValues(data, arr => _.map(arr, obj => _.assign({
  'algo_id': obj.id,
  'global_dag_conf': obj.config.global_dag_conf
})));

console.log(res);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.js"></script>

answered Mar 23, 2019 at 14:58

User863

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Comments

Ele · Accepted Answer · 2019-03-23 14:56:36Z

An alternative without lodash.

The function reduce allows to generate an object which will be filled using the function map which transforms the original objects to the desired structure.

const a =  {            "8": [{                "strategy": 123,                "id": 1,                "config": {                    "global_dag_conf": {                        "algo_v2_conf": {                            "features_to_combine": [],                            "segments": [],                            "force_performance": false,                            "min_bid": 0,                            "max_bid": 13                        }                    }                }            }],            "13": [{                "strategy": 456,                "id": 2,                "config": {                    "global_dag_conf": {                        "algo_v2_conf": {                            "ivr_measured": []                        }                    }                }            }]        };
        
let result = Object.entries(a).reduce((a, [key, arr]) => {
  return Object.assign(a, {[key]: arr.map(({id: algo_id, config}) => ({algo_id, ...config}))});
}, Object.create(null));
console.log(result);

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

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