Allows to apply given function to all values of given object including elements of an array and sub objects

apply-to-all-leaves.ts

const isObject = (subj: any) => typeof subj === 'object' && !Array.isArray(subj) && subj !== null;

export const applyToAllProps = (obj: Record<any, any>, fun: (props: any) => any) => {
  const appliedEntries: any = Object
    .entries(obj)
    .map(([key, value]) => ([key, applyToProp(value, fun)]));

  return Object.fromEntries(appliedEntries);
};

export const applyToProp = <T = any>(subj: any, fun: (props: any) => any): T | T[] => {
  if (isObject(subj)) {
    return applyToAllProps(subj, fun);
  }

  if (Array.isArray(subj)) {
    return subj.map(el => applyToProp<any>(el, fun));
  }

  return fun(subj);
};