Convert string into an object using reduce javascript

Question

I am trying to convert a string like "sheep" into an object like this:

{
   "s":{
      "initial":1,
      "final":1
   },
   "h":{
      "initial":1,
      "final":1
   },
   "e":{
      "initial":2,
      "final":2
   },
   "p":{
      "initial":1,
      "final":1
   }
}

Currently I can use reduce method in javascript and achive this:

const names = 'sheep'.split('');
const count = (names) =>
  names.reduce((acc, name) => ({ ...acc, [name]: (acc[name] || 0) + 1 }), {});
console.log(count(names)) //{ s: 1, h: 1, e: 2, p: 1 }

I have tried to read similar posts but I am pretty new to JS. Can anyone please help me? Thanks.

You are already pretty close, you just need to define the desired structure inside the reduce callback, but it is not clear what is the difference between initial and finalvalues. Can you elaborate on those? — Ma3x
– Ma3x, Commented Jan 28, 2022 at 13:08
I am going to modify the final count for my specific purpose. Sorry for using a simple example 😅 But the question has been answered. Thanks. — Shamim Akhtar
– Shamim Akhtar, Commented Jan 28, 2022 at 14:14

Amila Senadheera · Accepted Answer · 2022-01-28 13:13:01Z

2

Try like this

const names = "sheep".split("");
const count = (names) =>
  names.reduce(
    (acc, name) => ({
      ...acc,
      [name]: {
        initial: (acc?.[name]?.initial ?? 0) + 1,
        final: (acc?.[name]?.final ?? 0) + 1,
      },
    }),
    {}
  );
console.log(count(names));

answered Jan 28, 2022 at 13:13

Amila Senadheera

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Comments

Raul Rene · Accepted Answer · 2022-01-28 13:10:30Z

2

This works printing your desired output but I'm not sure why you want the initial and final counts to be the same

const letters = 'sheep'.split('');
const count = (letters) =>
  letters.reduce((obj, letter) => ({ ...obj, [letter]: {initial: (obj[letter]?.initial || 0) + 1, final: (obj[letter]?.final || 0) + 1} }), {});
console.log(count(letters))

Alternatively, you could expand a function there using braces and do some if's in order to have the code more readable instead of the ternaries

answered Jan 28, 2022 at 13:10

Raul Rene

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1 Comment

Shamim Akhtar Over a year ago

I am going to modify the final count for my specific purpose. Sorry for using a simple example 😅

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