/**
 * lodash (Custom Build) <https://lodash.com/>
 * Build: `lodash modularize exports="npm" -o ./`
 * Copyright jQuery Foundation and other contributors <https://jquery.org/>
 * Released under MIT license <https://lodash.com/license>
 * Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
 * Copyright Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 */

/**
 * The base implementation of `_.sortedUniq` and `_.sortedUniqBy` without
 * support for iteratee shorthands.
 *
 * @private
 * @param {Array} array The array to inspect.
 * @param {Function} [iteratee] The iteratee invoked per element.
 * @returns {Array} Returns the new duplicate free array.
 */
function baseSortedUniq(array, iteratee) {
  var index = -1,
      length = array.length,
      resIndex = 0,
      result = [];

  while (++index < length) {
    var value = array[index],
        computed = iteratee ? iteratee(value) : value;

    if (!index || !eq(computed, seen)) {
      var seen = computed;
      result[resIndex++] = value === 0 ? 0 : value;
    }
  }
  return result;
}

/**
 * This method is like `_.uniq` except that it's designed and optimized
 * for sorted arrays.
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Array
 * @param {Array} array The array to inspect.
 * @returns {Array} Returns the new duplicate free array.
 * @example
 *
 * _.sortedUniq([1, 1, 2]);
 * // => [1, 2]
 */
function sortedUniq(array) {
  return (array && array.length)
    ? baseSortedUniq(array)
    : [];
}

/**
 * Performs a
 * [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
 * comparison between two values to determine if they are equivalent.
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Lang
 * @param {*} value The value to compare.
 * @param {*} other The other value to compare.
 * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
 * @example
 *
 * var object = { 'a': 1 };
 * var other = { 'a': 1 };
 *
 * _.eq(object, object);
 * // => true
 *
 * _.eq(object, other);
 * // => false
 *
 * _.eq('a', 'a');
 * // => true
 *
 * _.eq('a', Object('a'));
 * // => false
 *
 * _.eq(NaN, NaN);
 * // => true
 */
function eq(value, other) {
  return value === other || (value !== value && other !== other);
}

module.exports = sortedUniq;
