// Version 1.3.1 index-array-by - https://github.com/vasturiano/index-array-by
(function (global, factory) {
  typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
  typeof define === 'function' && define.amd ? define(factory) :
  (global = typeof globalThis !== 'undefined' ? globalThis : global || self, global.indexBy = factory());
}(this, (function () { 'use strict';

  function _objectWithoutPropertiesLoose(source, excluded) {
    if (source == null) return {};
    var target = {};
    var sourceKeys = Object.keys(source);
    var key, i;

    for (i = 0; i < sourceKeys.length; i++) {
      key = sourceKeys[i];
      if (excluded.indexOf(key) >= 0) continue;
      target[key] = source[key];
    }

    return target;
  }

  function _objectWithoutProperties(source, excluded) {
    if (source == null) return {};

    var target = _objectWithoutPropertiesLoose(source, excluded);

    var key, i;

    if (Object.getOwnPropertySymbols) {
      var sourceSymbolKeys = Object.getOwnPropertySymbols(source);

      for (i = 0; i < sourceSymbolKeys.length; i++) {
        key = sourceSymbolKeys[i];
        if (excluded.indexOf(key) >= 0) continue;
        if (!Object.prototype.propertyIsEnumerable.call(source, key)) continue;
        target[key] = source[key];
      }
    }

    return target;
  }

  function _slicedToArray(arr, i) {
    return _arrayWithHoles(arr) || _iterableToArrayLimit(arr, i) || _unsupportedIterableToArray(arr, i) || _nonIterableRest();
  }

  function _toConsumableArray(arr) {
    return _arrayWithoutHoles(arr) || _iterableToArray(arr) || _unsupportedIterableToArray(arr) || _nonIterableSpread();
  }

  function _arrayWithoutHoles(arr) {
    if (Array.isArray(arr)) return _arrayLikeToArray(arr);
  }

  function _arrayWithHoles(arr) {
    if (Array.isArray(arr)) return arr;
  }

  function _iterableToArray(iter) {
    if (typeof Symbol !== "undefined" && iter[Symbol.iterator] != null || iter["@@iterator"] != null) return Array.from(iter);
  }

  function _iterableToArrayLimit(arr, i) {
    var _i = arr && (typeof Symbol !== "undefined" && arr[Symbol.iterator] || arr["@@iterator"]);

    if (_i == null) return;
    var _arr = [];
    var _n = true;
    var _d = false;

    var _s, _e;

    try {
      for (_i = _i.call(arr); !(_n = (_s = _i.next()).done); _n = true) {
        _arr.push(_s.value);

        if (i && _arr.length === i) break;
      }
    } catch (err) {
      _d = true;
      _e = err;
    } finally {
      try {
        if (!_n && _i["return"] != null) _i["return"]();
      } finally {
        if (_d) throw _e;
      }
    }

    return _arr;
  }

  function _unsupportedIterableToArray(o, minLen) {
    if (!o) return;
    if (typeof o === "string") return _arrayLikeToArray(o, minLen);
    var n = Object.prototype.toString.call(o).slice(8, -1);
    if (n === "Object" && o.constructor) n = o.constructor.name;
    if (n === "Map" || n === "Set") return Array.from(o);
    if (n === "Arguments" || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen);
  }

  function _arrayLikeToArray(arr, len) {
    if (len == null || len > arr.length) len = arr.length;

    for (var i = 0, arr2 = new Array(len); i < len; i++) arr2[i] = arr[i];

    return arr2;
  }

  function _nonIterableSpread() {
    throw new TypeError("Invalid attempt to spread non-iterable instance.\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method.");
  }

  function _nonIterableRest() {
    throw new TypeError("Invalid attempt to destructure non-iterable instance.\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method.");
  }

  function _toPrimitive(input, hint) {
    if (typeof input !== "object" || input === null) return input;
    var prim = input[Symbol.toPrimitive];

    if (prim !== undefined) {
      var res = prim.call(input, hint || "default");
      if (typeof res !== "object") return res;
      throw new TypeError("@@toPrimitive must return a primitive value.");
    }

    return (hint === "string" ? String : Number)(input);
  }

  function _toPropertyKey(arg) {
    var key = _toPrimitive(arg, "string");

    return typeof key === "symbol" ? key : String(key);
  }

  var index = (function () {
    var list = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : [];
    var keyAccessors = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : [];
    var multiItem = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : true;
    var flattenKeys = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : false;
    var keys = (keyAccessors instanceof Array ? keyAccessors.length ? keyAccessors : [undefined] : [keyAccessors]).map(function (key) {
      return {
        keyAccessor: key,
        isProp: !(key instanceof Function)
      };
    });
    var indexedResult = list.reduce(function (res, item) {
      var iterObj = res;
      var itemVal = item;
      keys.forEach(function (_ref, idx) {
        var keyAccessor = _ref.keyAccessor,
            isProp = _ref.isProp;
        var key;

        if (isProp) {
          var _itemVal = itemVal,
              propVal = _itemVal[keyAccessor],
              rest = _objectWithoutProperties(_itemVal, [keyAccessor].map(_toPropertyKey));

          key = propVal;
          itemVal = rest;
        } else {
          key = keyAccessor(itemVal, idx);
        }

        if (idx + 1 < keys.length) {
          if (!iterObj.hasOwnProperty(key)) {
            iterObj[key] = {};
          }

          iterObj = iterObj[key];
        } else {
          // Leaf key
          if (multiItem) {
            if (!iterObj.hasOwnProperty(key)) {
              iterObj[key] = [];
            }

            iterObj[key].push(itemVal);
          } else {
            iterObj[key] = itemVal;
          }
        }
      });
      return res;
    }, {});

    if (multiItem instanceof Function) {
      // Reduce leaf multiple values
      (function reduce(node) {
        var level = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : 1;

        if (level === keys.length) {
          Object.keys(node).forEach(function (k) {
            return node[k] = multiItem(node[k]);
          });
        } else {
          Object.values(node).forEach(function (child) {
            return reduce(child, level + 1);
          });
        }
      })(indexedResult); // IIFE

    }

    var result = indexedResult;

    if (flattenKeys) {
      // flatten into array
      result = [];

      (function flatten(node) {
        var accKeys = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : [];

        if (accKeys.length === keys.length) {
          result.push({
            keys: accKeys,
            vals: node
          });
        } else {
          Object.entries(node).forEach(function (_ref2) {
            var _ref3 = _slicedToArray(_ref2, 2),
                key = _ref3[0],
                val = _ref3[1];

            return flatten(val, [].concat(_toConsumableArray(accKeys), [key]));
          });
        }
      })(indexedResult); //IIFE


      if (keyAccessors instanceof Array && keyAccessors.length === 0 && result.length === 1) {
        // clear keys if there's no key accessors (single result)
        result[0].keys = [];
      }
    }

    return result;
  });

  return index;

})));
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