countDistinct.js

/**
 * Copyright (c) 2013-present, Facebook, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * 
 */
'use strict';

var Set = require("./Set");

var emptyFunction = require("./emptyFunction");
/**
 * Returns the count of distinct elements selected from an array.
 */


function countDistinct(iter, selector) {
  selector = selector || emptyFunction.thatReturnsArgument;
  var set = new Set();
  var _iteratorNormalCompletion = true;
  var _didIteratorError = false;
  var _iteratorError = undefined;

  try {
    for (var _iterator = iter[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
      var val = _step.value;
      set.add(selector(val));
    }
  } catch (err) {
    _didIteratorError = true;
    _iteratorError = err;
  } finally {
    try {
      if (!_iteratorNormalCompletion && _iterator["return"] != null) {
        _iterator["return"]();
      }
    } finally {
      if (_didIteratorError) {
        throw _iteratorError;
      }
    }
  }

  return set.size;
}

module.exports = countDistinct;