lodash/isEmpty.js

import isArguments from './isArguments';
import isArray from './isArray';
import isArrayLike from './isArrayLike';
import isFunction from './isFunction';
import isString from './isString';

/** Used for built-in method references. */
var objectProto = Object.prototype;

/** Used to check objects for own properties. */
var hasOwnProperty = objectProto.hasOwnProperty;

/**
 * Checks if `value` is empty. A value is considered empty unless it's an
 * `arguments` object, array, string, or jQuery-like collection with a length
 * greater than `0` or an object with own enumerable properties.
 *
 * @static
 * @memberOf _
 * @category Lang
 * @param {Array|Object|string} value The value to inspect.
 * @returns {boolean} Returns `true` if `value` is empty, else `false`.
 * @example
 *
 * _.isEmpty(null);
 * // => true
 *
 * _.isEmpty(true);
 * // => true
 *
 * _.isEmpty(1);
 * // => true
 *
 * _.isEmpty([1, 2, 3]);
 * // => false
 *
 * _.isEmpty({ 'a': 1 });
 * // => false
 */
function isEmpty(value) {
  if (isArrayLike(value) &&
      (isArray(value) || isString(value) || isFunction(value.splice) || isArguments(value))) {
    return !value.length;
  }
  for (var key in value) {
    if (hasOwnProperty.call(value, key)) {
      return false;
    }
  }
  return true;
}

export default isEmpty;