source: node_modules/classnames/dedupe.js

/*!
        Copyright (c) 2018 Jed Watson.
        Licensed under the MIT License (MIT), see
        http://jedwatson.github.io/classnames
*/
/* global define */

(function () {
        'use strict';

        var classNames = (function () {
                // don't inherit from Object so we can skip hasOwnProperty check later
                // http://stackoverflow.com/questions/15518328/creating-js-object-with-object-createnull#answer-21079232
                function StorageObject() {}
                StorageObject.prototype = Object.create(null);

                function _parseArray (resultSet, array) {
                        var length = array.length;

                        for (var i = 0; i < length; ++i) {
                                _parse(resultSet, array[i]);
                        }
                }

                var hasOwn = {}.hasOwnProperty;

                function _parseNumber (resultSet, num) {
                        resultSet[num] = true;
                }

                function _parseObject (resultSet, object) {
                        if (object.toString !== Object.prototype.toString && !object.toString.toString().includes('[native code]')) {
                                resultSet[object.toString()] = true;
                                return;
                        }

                        for (var k in object) {
                                if (hasOwn.call(object, k)) {
                                        // set value to false instead of deleting it to avoid changing object structure
                                        // https://www.smashingmagazine.com/2012/11/writing-fast-memory-efficient-javascript/#de-referencing-misconceptions
                                        resultSet[k] = !!object[k];
                                }
                        }
                }

                var SPACE = /\s+/;
                function _parseString (resultSet, str) {
                        var array = str.split(SPACE);
                        var length = array.length;

                        for (var i = 0; i < length; ++i) {
                                resultSet[array[i]] = true;
                        }
                }

                function _parse (resultSet, arg) {
                        if (!arg) return;
                        var argType = typeof arg;

                        // 'foo bar'
                        if (argType === 'string') {
                                _parseString(resultSet, arg);

                        // ['foo', 'bar', ...]
                        } else if (Array.isArray(arg)) {
                                _parseArray(resultSet, arg);

                        // { 'foo': true, ... }
                        } else if (argType === 'object') {
                                _parseObject(resultSet, arg);

                        // '130'
                        } else if (argType === 'number') {
                                _parseNumber(resultSet, arg);
                        }
                }

                function _classNames () {
                        // don't leak arguments
                        // https://github.com/petkaantonov/bluebird/wiki/Optimization-killers#32-leaking-arguments
                        var len = arguments.length;
                        var args = Array(len);
                        for (var i = 0; i < len; i++) {
                                args[i] = arguments[i];
                        }

                        var classSet = new StorageObject();
                        _parseArray(classSet, args);

                        var list = [];

                        for (var k in classSet) {
                                if (classSet[k]) {
                                        list.push(k)
                                }
                        }

                        return list.join(' ');
                }

                return _classNames;
        })();

        if (typeof module !== 'undefined' && module.exports) {
                classNames.default = classNames;
                module.exports = classNames;
        } else if (typeof define === 'function' && typeof define.amd === 'object' && define.amd) {
                // register as 'classnames', consistent with npm package name
                define('classnames', [], function () {
                        return classNames;
                });
        } else {
                window.classNames = classNames;
        }
}());