Sort an object by keys

prettySortByKeys.js

const sortByKeysLegibly = maybeObject => {
  // presumably we want the array to stay ordered. Possibly not, but if there is
  // anything that should preserve order, it's an array
  if (maybeObject instanceof Array) {
    return maybeObject;
  }

  // don't sort strings etc
  if (typeof maybeObject !== 'object') {
    return maybeObject;
  }

  const sortedKeys = Object.keys(maybeObject).sort();

  return sortedKeys.reduce((objectSoFar, currentKey) => {
    const currentValue = maybeObject[currentKey];
    const maybeSortedValue = sortByKeysLegibly(currentValue);
    return {
      ...objectSoFar,
      [currentKey]: maybeSortedValue
    };
  }, {});
};

// and for JSON
const sortJson = jsonValue => JSON.stringify(sortByKeysLegibly(JSON.parse(jsonValue)));

sortByKey.js

// ugly code golf version
const sortKeys = v =>
  v instanceof Array || typeof v !== 'object'
    ? v
    : Object.keys(v)
        .sort()
        .reduce(
          (acc, k) => ({
            ...acc,
            [k]: sortKeys(v[k])
          }),
          {}
        );