TypeScript set nested key

setNestedKey.ts

/**
 * Sets a value of nested key string descriptor inside a Object.
 * It changes the passed object.
 * Ex1:
 *    let obj = {a: {b:{c:'initial'}}};
 *    setNestedKey(obj, ['a', 'b', 'c'], 'changed-value');
 *    assert(obj === {a: {b:{c:'changed-value'}}});
 * 
 * Ex2:
 *    let obj = null;
 *    setNestedKey(obj, ['a', 'b', 'c'], 'new-value');
 *    assert(obj === {a: {b:{c:'new-value'}}});
 *
 * @param {[Object]} obj   Object to set the nested key
 * @param {[Array]} path  An array to describe the path(Ex: ['a', 'b', 'c'])
 * @param {[Object]} value Any value
 */
const setNestedKey: (obj: any, path: string[], value: any) => void
 = (obj, path, value) => {
  if (path.length === 1) {
    obj[path[0]] = value;
    return;
  }
  if (!obj[path[0]]) {
    obj[path[0]] = {};
  }
  return setNestedKey(obj[path[0]], path.slice(1), value);
}

export default (obj: any, path: string[], value: unknown) => {
  if (!obj) {
    obj = {};
  }
  return setNestedKey(obj, path, value);
}

// Credit: https://stackoverflow.com/a/49754647/6514473