jpath.js

/**
 * @example
 * // 1
 * jpath('.foo.bar', { foo: { bar: 1 } });
 *
 * // null
 * jpath('.foo.bar.baz', { foo: 2 })
 */
const jpath = (function() {
  function recursiveSearch(fields, source) {
    const next = source[fields.shift()];

    if (fields.length) {
      if (typeof next === "object") {
        return recursiveSearch(fields, next);
      }
      return null;
    }
    return next;
  }

  return function(jpath, source) {
    return recursiveSearch(jpath.split('.').filter(Boolean), source);
  }
}());