(function (global, factory) {
  typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
  typeof define === 'function' && define.amd ? define(['exports'], factory) :
  (global = typeof globalThis !== 'undefined' ? globalThis : global || self, factory(global.fastSort = {}));
}(this, (function (exports) { 'use strict';

  // >>> INTERFACES <<<
  // >>> HELPERS <<<
  var castComparer = function (comparer) { return function (a, b, order) { return comparer(a, b, order) * order; }; };
  var throwInvalidConfigErrorIfTrue = function (condition, context) {
      if (condition)
          throw Error("Invalid sort config: " + context);
  };
  var unpackObjectSorter = function (sortByObj) {
      var _a = sortByObj || {}, asc = _a.asc, desc = _a.desc;
      var order = asc ? 1 : -1;
      var sortBy = (asc || desc);
      // Validate object config
      throwInvalidConfigErrorIfTrue(!sortBy, 'Expected `asc` or `desc` property');
      throwInvalidConfigErrorIfTrue(asc && desc, 'Ambiguous object with `asc` and `desc` config properties');
      var comparer = sortByObj.comparer && castComparer(sortByObj.comparer);
      return { order: order, sortBy: sortBy, comparer: comparer };
  };
  // >>> SORTERS <<<
  var multiPropertySorterProvider = function (defaultComparer) {
      return function multiPropertySorter(sortBy, sortByArr, depth, order, comparer, a, b) {
          var valA;
          var valB;
          if (typeof sortBy === 'string') {
              valA = a[sortBy];
              valB = b[sortBy];
          }
          else if (typeof sortBy === 'function') {
              valA = sortBy(a);
              valB = sortBy(b);
          }
          else {
              var objectSorterConfig = unpackObjectSorter(sortBy);
              return multiPropertySorter(objectSorterConfig.sortBy, sortByArr, depth, objectSorterConfig.order, objectSorterConfig.comparer || defaultComparer, a, b);
          }
          var equality = comparer(valA, valB, order);
          if ((equality === 0 || (valA == null && valB == null)) &&
              sortByArr.length > depth) {
              return multiPropertySorter(sortByArr[depth], sortByArr, depth + 1, order, comparer, a, b);
          }
          return equality;
      };
  };
  function getSortStrategy(sortBy, comparer, order) {
      // Flat array sorter
      if (sortBy === undefined || sortBy === true) {
          return function (a, b) { return comparer(a, b, order); };
      }
      // Sort list of objects by single object key
      if (typeof sortBy === 'string') {
          throwInvalidConfigErrorIfTrue(sortBy.includes('.'), 'String syntax not allowed for nested properties.');
          return function (a, b) { return comparer(a[sortBy], b[sortBy], order); };
      }
      // Sort list of objects by single function sorter
      if (typeof sortBy === 'function') {
          return function (a, b) { return comparer(sortBy(a), sortBy(b), order); };
      }
      // Sort by multiple properties
      if (Array.isArray(sortBy)) {
          var multiPropSorter_1 = multiPropertySorterProvider(comparer);
          return function (a, b) { return multiPropSorter_1(sortBy[0], sortBy, 1, order, comparer, a, b); };
      }
      // Unpack object config to get actual sorter strategy
      var objectSorterConfig = unpackObjectSorter(sortBy);
      return getSortStrategy(objectSorterConfig.sortBy, objectSorterConfig.comparer || comparer, objectSorterConfig.order);
  }
  var sortArray = function (order, ctx, sortBy, comparer) {
      var _a;
      if (!Array.isArray(ctx)) {
          return ctx;
      }
      // Unwrap sortBy if array with only 1 value to get faster sort strategy
      if (Array.isArray(sortBy) && sortBy.length < 2) {
          _a = sortBy, sortBy = _a[0];
      }
      return ctx.sort(getSortStrategy(sortBy, comparer, order));
  };
  function createNewSortInstance(opts) {
      var comparer = castComparer(opts.comparer);
      return function (arrayToSort) {
          var ctx = Array.isArray(arrayToSort) && !opts.inPlaceSorting
              ? arrayToSort.slice()
              : arrayToSort;
          return {
              asc: function (sortBy) {
                  return sortArray(1, ctx, sortBy, comparer);
              },
              desc: function (sortBy) {
                  return sortArray(-1, ctx, sortBy, comparer);
              },
              by: function (sortBy) {
                  return sortArray(1, ctx, sortBy, comparer);
              },
          };
      };
  }
  var defaultComparer = function (a, b, order) {
      if (a == null)
          return order;
      if (b == null)
          return -order;
      if (typeof a !== typeof b) {
          return typeof a < typeof b ? -1 : 1;
      }
      if (a < b)
          return -1;
      if (a > b)
          return 1;
      return 0;
  };
  var sort = createNewSortInstance({
      comparer: defaultComparer,
  });
  var inPlaceSort = createNewSortInstance({
      comparer: defaultComparer,
      inPlaceSorting: true,
  });

  exports.createNewSortInstance = createNewSortInstance;
  exports.defaultComparer = defaultComparer;
  exports.inPlaceSort = inPlaceSort;
  exports.sort = sort;

  Object.defineProperty(exports, '__esModule', { value: true });

})));