How to combine multiple JSON objects where key value is the same

Question

I'm trying to combine objects which share the same module key value, i.e. "credit cards". I need to return a single object per unique module with an array of distinct companies. The id and prod keys aren't important.

Here's the object I need to transform:

const data = [
   {module: "credit_cards", id: "1", company: "ABC", prod: "1"}, 
   {module: "credit_cards", id: "2", company: "XYZ", prod: "2"}, 
   {module: "credit_cards", id: "3", company: "EFG", prod: "2"}, 
   {module: "credit_cards", id: "2", company: "XYZ", prod: "2"}, 
   {module: "mortgages", id: "4", company: "EFG", prod: "3"}
]

I need to return something like this:

const result = [
{module: "credit_cards", company: ["ABC", "XYZ", "EFG"]}, 
{module: "mortgages", company: ["EFG"]}
]

So far, I've tried this function:

const result = data.reduce(function(r, e) {
  return Object.keys(e).forEach(function(k) {
    if(!r[k]) r[k] = [].concat(e[k])
    else r[k] = r[k].concat(e[k])
  }), r
}, {})

But it just concatenated all the key/values together...

Any help would be awesome, thanks :)

One key is company, while the others' keys are co_code, what's the logic behind that? — CertainPerformance
– CertainPerformance, Commented May 14, 2019 at 4:27

Shidersz · Accepted Answer · 2019-05-14 04:34:27Z

You can use first Array.reduce() to group the companies by the module key on a Set. On a second step you can use array.Map() over the generated object .entries() to get the final desired result:

const data = [
   {module: "credit_cards", id: "1", company: "ABC", prod: "1"}, 
   {module: "credit_cards", id: "2", company: "XYZ", prod: "2"}, 
   {module: "credit_cards", id: "3", company: "EFG", prod: "2"}, 
   {module: "credit_cards", id: "2", company: "XYZ", prod: "2"}, 
   {module: "mortgages", id: "4", company: "EFG", prod: "3"}
];

let res = data.reduce((acc, {module, company}) =>
{
    acc[module] = acc[module] || new Set();
    acc[module].add(company);
    return acc;
}, {})

res = Object.entries(res).map(
    ([module, companies]) => ({module, company: [...companies]})
);

console.log(res);

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

CertainPerformance · Accepted Answer · 2019-05-14 04:43:45Z

3

Reduce into an object indexed by module, then take that object's values. Because you only want unique company values, use a Set initially, and then transform all items' company sets back into an array afterwards:

const data = [
   {module: "credit_cards", id: "1", company: "ABC", prod: "1"}, 
   {module: "credit_cards", id: "2", company: "XYZ", prod: "2"}, 
   {module: "credit_cards", id: "3", company: "EFG", prod: "2"}, 
   {module: "credit_cards", id: "2", company: "XYZ", prod: "2"}, 
   {module: "mortgages", id: "4", company: "EFG", prod: "3"}
]

const result = Object.values(data.reduce(
  (a, { module, company }) => {
    if (!a[module]) a[module] = { module, company: new Set() };
    a[module].company.add(company);
    return a;
  },
  {}
));

result.forEach((item) => {
  item.company = [...item.company];
});
console.log(result);

edited May 14, 2019 at 4:43

answered May 14, 2019 at 4:31

CertainPerformance

373k55 gold badges354 silver badges359 bronze badges

1 Comment

Shidersz Over a year ago

Note XYZ is duplicated on your co_code array. I believe, in relation to his desired output, he don't want duplicated values on the arrays.

Eddie · Accepted Answer · 2019-05-14 05:35:37Z

3

You can use reduce to summarize the array into a Map. Use Set for unique values.

const data = [{"module":"credit_cards","id":"1","comapany":"ABC","prod":"1"},{"module":"credit_cards","id":"2","comapany":"XYZ","prod":"2"},{"module":"credit_cards","id":"3","comapany":"EFG","prod":"2"},{"module":"credit_cards","id":"2","comapany":"XYZ","prod":"2"},{"module":"mortgages","id":"4","comapany":"EFG","prod":"3"}]

const result = Array.from(data.reduce((c, {module,comapany}) => {
  if (!c.has(module)) c.set(module, new Set);
  c.get(module).add(comapany);
  return c;
}, new Map)).map(([module, comapany]) => ({module,comapany: [...comapany]}));

console.log(result);

edited May 14, 2019 at 5:35

answered May 14, 2019 at 4:31

Eddie

26.8k6 gold badges39 silver badges59 bronze badges

Comments

Akrion · Accepted Answer · 2019-05-14 05:13:59Z

0

Here is another approach with Array.reduce and with internal check to make sure the list of the companies is unique and without duplicates.

const data = [ {module: "credit_cards", id: "1", company: "ABC", prod: "1"}, {module: "credit_cards", id: "2", company: "XYZ", prod: "2"}, {module: "credit_cards", id: "3", company: "EFG", prod: "2"}, {module: "credit_cards", id: "2", company: "XYZ", prod: "2"}, {module: "mortgages", id: "4", company: "EFG", prod: "3"} ]

let result = data.reduce((r,{module, company}) => {
  r[module] = r[module] || { module, company: [] }
  if(!r[module].company.includes(company))
    r[module].company.push(company)
  return r
}, {})

console.log(Object.values(result))

edited May 14, 2019 at 5:13

answered May 14, 2019 at 5:08

Akrion

18.6k1 gold badge38 silver badges58 bronze badges

Comments

Yves Israel · Accepted Answer · 2019-05-14 05:19:58Z

0

   const data = [
  {module: 'credit_cards', id: '1', company: 'ABC', prod: '1'},
  {module: 'credit_cards', id: '2', company: 'XYZ', prod: '2'},
  {module: 'credit_cards', id: '3', company: 'EFG', prod: '2'},
  {module: 'credit_cards', id: '2', company: 'XYZ', prod: '2'},
  {module: 'mortgages', id: '4', company: 'EFG', prod: '3'}
  ];



 const result = data.reduce((array, item) => {
     const id = array.findIndex(el => el.module === item.module);
     if (id > -1) {
       array[id] = {...array[id], company : [...array[id].company, item.company]};
       return array;
     }
     return [...array, {...item, company : [ item.company]}];
    }, []);

answered May 14, 2019 at 5:19

Yves Israel

4183 silver badges5 bronze badges

Collectives™ on Stack Overflow

How to combine multiple JSON objects where key value is the same

5 Answers 5

Comments

1 Comment

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

5 Answers 5

Comments

1 Comment

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related