Rebuilding objects

I am trying to rebuild the output of frequency counter which is in this case an object, alphabetically, I extracted the keys using Object.keys sorted them but I don’t know how to put them back with their corresponding values into an object, do I have to construct an algorithm or there are some methods that can do that?

function letterCount(str){
    var frequency = {};
    for (let char of str.toLowerCase()){
        frequency[char]>0 ? frequency[char]++ : frequency[char] = 1;
    let keys = Object.keys(frequency)
        if(a<b) return -1; else return 1;

    return frequency;

console.log(letterCount('Some string'))

It seems you need to add the keys to the object in a certain order if you want to have the keys in a specific order:

Maybe convert the string in an array and sort the characters before adding properties to the object?
Maybe instead of an object create a multidimensional array? [["s", 2], ["a", 1], ...] - an array you can give a specific order

Slight amendment to what you already have (using entries rather than keys is probably easier):

function letterCount(str){
    let frequency = {};

    // I'm running this once rather than on every iteration of the loop:
    const lcStr = str.toLowerCase();

    // As before, count frequencies:
    for (const char of lcStr){
        char in frequency ? frequency[char]++ : frequency[char] = 1;

    // I'm not sure why you don't just return `frequency` here, but anyway...

    // Convert the frequency object to an array of [k, v] and sort:
    const sortedFrequencies = Object.entries(frequency).sort(([a], [b]) => (a < b) ? -1 : (a > b) ? : 0);
    // Reset frequency to empty:
    frequency = {}

    // Put the now-sorted k:v entries back in:
    for (const [k, v] of sortedFrequencies) {
      frequency[k] = v;

    return frequency;

The question though is why you want to do this beyond it looking pretty in the console. Objects respect insertion order, but there isn’t really a good usecase for the extra computation: it’s very unusual to rely on the ordering of objects, that’s not what they’re designed for.


function letterCount(str){
  // Build a map of characters like `{a: 0, b: 0, c: 0, ...}`
  const frequencies = [...'abcdefghijklmnopqrsuvwxyz'].reduce((acc, char) => ({...acc, [char]: 0}), {});
  // Loop through the string and increment the relevant field in the map:
  for (const char of lcStr) frequencies[char.toLowerCase()]++;

  return frequencies;