lodash/_hasPath.js

var castPath = require('./_castPath'),
    isArguments = require('./isArguments'),
    isArray = require('./isArray'),
    isIndex = require('./_isIndex'),
    isKey = require('./_isKey'),
    isLength = require('./isLength'),
    toKey = require('./_toKey');

/**
 * Checks if `path` exists on `object`.
 *
 * @private
 * @param {Object} object The object to query.
 * @param {Array|string} path The path to check.
 * @param {Function} hasFunc The function to check properties.
 * @returns {boolean} Returns `true` if `path` exists, else `false`.
 */
function hasPath(object, path, hasFunc) {
  path = isKey(path, object) ? [path] : castPath(path);

  var index = -1,
      length = path.length,
      result = false;

  while (++index < length) {
    var key = toKey(path[index]);
    if (!(result = object != null && hasFunc(object, key))) {
      break;
    }
    object = object[key];
  }
  if (result || ++index != length) {
    return result;
  }
  length = object == null ? 0 : object.length;
  return !!length && isLength(length) && isIndex(key, length) &&
    (isArray(object) || isArguments(object));
}

module.exports = hasPath;