How to group JSON keys as a new key by its prefix or key?

Question

So I have a query output somewhat like this (using knex):

response = [
  {id: 1, source: 'mobile', ms_payment.id: 111, ms_payment.total: 100},
  {id: 2, source: 'mobile', ms_payment.id: 112, ms_payment.total: 210},
  ...
]

And the expected output (mapped output) to return in REST API is:

result = [
  {id: 1, source: 'mobile', ms_payment: { id: 111, total: 100 }},
  {id: 2, source: 'mobile', ms_payment: { id: 112, total: 210 }},
]

Is there any efficient algorithm using javascript? I am currently doing it manually with Array.map(), which just returns the expected output schema, without any looping or methods.

Thank you in advance.

there is no other method. the only method is that you must loop through properties — Nbody, Oct 19 '20 at 08:51
@Ifaruki it's valid. To access the property you need to use bracket notation `obj["ms_payment.id"]` — adiga, Oct 19 '20 at 09:03
@adiga well what i mean is that he doesnt stringified it he just wrote it it how it is ` ms_payment.id: 112` witch leads to `SnytaxError: Unexpected token "."` — bill.gates, Oct 19 '20 at 09:06
@Ifaruki yeah, the object literal in the question is invalid. — adiga, Oct 19 '20 at 09:12

score 2 · Accepted Answer · answered Oct 19 '20 at 08:55

You need to iterate the entries and get nested objects.

const
    setValue = (object, key, value) => {
        const
            keys = key.split('.'),
            last = keys.pop();
            
        keys.reduce((o, k) => o[k] ??= {}, object)[last] = value;
        return object;
    },
    response = [{ id: 1, source: 'mobile', 'ms_payment.id': 111, 'ms_payment.total': 100 }, { id: 2, source: 'mobile', 'ms_payment.id': 112, 'ms_payment.total': 210 }],
    result = response.map(o => Object
        .entries(o)
        .reduce((r, [k, v]) => setValue(r, k, v), {})
    );

console.log(result);

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

score 1 · Answer 2 · answered Oct 19 '20 at 09:01

You can use the map function.

let response = [
  {id: 1, source: 'mobile', "ms_payment.id": 111, "ms_payment.total": 100},
  {id: 2, source: 'mobile', "ms_payment.id": 112, "ms_payment.total": 210},
];
let newResponse = [];
newResponse = response.map(obj => {
  let newObj = {...obj};
  Object.keys(obj).map(objKey => {
    if (objKey.toString().indexOf(".") >= 0) {
      let nodes = objKey.toString().split(".");
      let parent = nodes[0];
      let child = nodes[1];
      if (newObj.parent) {
        newObj.parent[child] = obj[objKey];
      } else {
        newObj.parent = {};
        newObj.parent[child] = obj[objKey];
      }
      delete newObj[objKey];
    }
  })
  return newObj;
});
console.log(newResponse);

score 0 · Answer 3 · answered Oct 19 '20 at 08:57

You can map your array like this:

response = [{
    id: 1,
    source: 'mobile',
    'ms_payment.id': 111,
    'ms_payment.total': 100
  },
  {
    id: 2,
    source: 'mobile',
    'ms_payment.id': 112,
    'ms_payment.total': 210
  },
];

const result = response.map((item) => {
  return {
    id: item.id,
    source: item.source,
    ms_payment: {
      id: item['ms_payment.id'],
      total: item['ms_payment.total']
    }
  }
});

console.log(result);

How to group JSON keys as a new key by its prefix or key?

3 Answers3