objects flattening

_objectsFlattening.js

const obj = { a: { b: 1, c: 2, d: { e:4 , f:[1,2,3,4,5,6,7,8,9,0]} }, g:42 };

const res = Object.fromEntries(flatProps(objectRecursiveEntries(obj)));
/*
{
    "a.b": 1,
    "a.c": 2,
    "a.d.e": 4,
    "a.d.f.0": 1,
    "a.d.f.1": 2,
    "a.d.f.2": 3,
    "a.d.f.3": 4,
    "a.d.f.4": 5,
    "a.d.f.5": 6,
    "a.d.f.6": 7,
    "a.d.f.7": 8,
    "a.d.f.8": 9,
    "a.d.f.9": 0,
    "g": 42,
}
*/

flatProps.js

function flatProps(arr = [], parentKey = null) {

  const res = [];

  for (const [key, value] of arr) {
    if(Array.isArray(value)) {
      res.push(...flatProps(value, key).map(([k, v]) => {
        const keyToInsert = parentKey ? `${parentKey}.${k}` : k;
        return [keyToInsert, v];
      }));
    } else {
      const keyToInsert = parentKey ? `${parentKey}.${key}` : key;
      res.push([keyToInsert, value]);
    }
  }

  return res;
}

objectRecursiveEntries.js

function objectRecursiveEntries(obj = {}) {

  const res = [];

  for(const [key, value] of Object.entries(obj)) {
    if(value && typeof value === "object") {
      res.push([key, recursiveEntries(value)])
    } else {
      res.push([key, value]);
    }
  }

  return res;
}