getRelativePath util for lodash `get` function

getRelativePath.js

/**
 * @param {string} [path='']
 * @return {boolean}
 * @author Wallace Ferreira <https://github.com/wallace-sf>
 * @example
 * isRelativePath('.')
 * => true
 * isRelativePath('..')
 * => true
 * isRelativePath('a...')
 * => false
 * isRelativePath('...c')
 * => false
 * isRelativePath('a...c')
 * => false
 */
const isRelativePath = (path = '') => {
  return /^(([.](?=\.))?(\.)+)$/g.test(path);
};

/**
 * @description Get a parent path from child path (e.g., `address.street` with part
 * `..` should return `address`).
 * @param {string} path
 * @param {...string} parts
 * @return {string} parentPath
 * @author Wallace Ferreira <https://github.com/wallace-sf>
 * @example
 * getParentPath('car.model', 'brand', 'name)
 * => 'car.model.brand.name'
 * getParentPath('car.model', '.', 'brand', 'name')
 * => 'car.model.brand.name'
 * getParentPath('car.model', '..', 'brand', 'name')
 * => 'car.brand.name'
 * getParentPath('car.model', '...', 'brand', 'name')
 * => 'brand.name'
 * getRelativePath('car.model', '.', 'brand', 'name', '..')
 * => 'car.model.brand'
 * getParentPath('car.model', '...')
 * => ''
 */
export const getRelativePath = (path = '', ...parts) => {
  return parts
    .reduce((acc, part) => {
      if (isRelativePath(part)) {
        const endIndexNewPath = acc.length - (part.length - 1);

        return acc.slice(0, endIndexNewPath > 0 ? endIndexNewPath : 0);
      }

      return [...acc, part];
    }, path.split('.'))
    .join('.');
};