TypeScript function to clone a JavaScript object

deep-clone-object.ts

type Source = { [key: string]: string | number | boolean | object };

export function cloneObject<T>(o: Source): T {
  const objectCopy = Object.create({});
  
  Object.keys(o).forEach((key) => {
    if (typeof o[key] !== 'object' || o[key] === null) {
      objectCopy[key] = o[key];
    } else if (Array.isArray(o[key])) {
      objectCopy[key] = o[key].map(a => typeof a === 'object' ? cloneObject(a) : a);
    } else {
      objectCopy[key] = cloneObject(o[key] as Source);
    }
  });
  
  return objectCopy as T;
}