Merge keys in JSON object to return an array of merged keys and the value with Javascript

Question

I want to convert the input to output with Javascript. Any help? Input can have more nested objects too.

const input = {
   a: {
     b: 22,
     c: 'hello',
   },
   e: 456
}

const output = [
    { 'a.b': 22},
    { 'a.c': 'hello' },
    { 'e': 456 }
];

Instead of giving just an input and output, could you please provide what you've tried? — zfrisch
– zfrisch, Commented Mar 23, 2020 at 20:08
what is the goal here? why do you want to do something like this? Is this just a homework / interview problem or is this for an actual system? you'd want to use recursion here and keep converting children through a tree essentially — John Ruddell
– John Ruddell, Commented Mar 23, 2020 at 20:08

Nenad Vracar · Accepted Answer · 2020-03-23 20:10:38Z

1

You could create recursive function using reduce method for this.

const input = {
  a: {
    b: true,
    c: 'hi',
  },
  d: 123
}

function convert(data, prev = '') {
  return Object.entries(data).reduce((r, [k, v]) => {
    let key = prev + (prev ? '.' : '') + k;

    if (typeof v == 'object') {
      r.push(...convert(v, key))
    } else {
      r.push({ [key]: v })
    }

    return r;
  }, [])
}

const result = convert(input)
console.log(result)

answered Mar 23, 2020 at 20:10

Nenad Vracar

122k16 gold badges160 silver badges184 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

xdeepakv · Accepted Answer · 2020-03-23 22:22:27Z

// Best and Fast way to solve'

Object.entries(data).reduce((r, [k, v]) => { is slower with big json.

Benchmark

NO MORE OVER LOOP FOR Object.entries()

const input = { a: { b: 22, c: "hello", d: { f: 10 } }, e: 456 };
function flat(data, key = "", result = []) {
  for (let k in data) {
    if (typeof data[k] === "object") {
      flat(data[k], key + k + ".", result);
    } else result.push({ [key + k]: data[k] });
  }
  return result;
}
console.log(flat(input));

const input = { a: { b: 22, c: "hello", d: { f: 10 } }, e: 456 };
function flat(data, key = "", result = []) {
  for (let k in data) {
    if (typeof data[k] === "object") {
      flat(data[k], key + k + ".", result);
    } else result.push({ [key + k]: data[k] });
  }
  return result;
}
console.log(flat(input));

Collectives™ on Stack Overflow

Merge keys in JSON object to return an array of merged keys and the value with Javascript

2 Answers 2

Comments

Benchmark

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Benchmark

Comments

Your Answer

Sign up or log in

Post as a guest

Related