source: trip-planner-front/node_modules/extend/index.js@ eed0bf8

'use strict';

var hasOwn = Object.prototype.hasOwnProperty;
var toStr = Object.prototype.toString;
var defineProperty = Object.defineProperty;
var gOPD = Object.getOwnPropertyDescriptor;

var isArray = function isArray(arr) {
        if (typeof Array.isArray === 'function') {
                return Array.isArray(arr);
        }

        return toStr.call(arr) === '[object Array]';
};

var isPlainObject = function isPlainObject(obj) {
        if (!obj || toStr.call(obj) !== '[object Object]') {
                return false;
        }

        var hasOwnConstructor = hasOwn.call(obj, 'constructor');
        var hasIsPrototypeOf = obj.constructor && obj.constructor.prototype && hasOwn.call(obj.constructor.prototype, 'isPrototypeOf');
        // Not own constructor property must be Object
        if (obj.constructor && !hasOwnConstructor && !hasIsPrototypeOf) {
                return false;
        }

        // Own properties are enumerated firstly, so to speed up,
        // if last one is own, then all properties are own.
        var key;
        for (key in obj) { /**/ }

        return typeof key === 'undefined' || hasOwn.call(obj, key);
};

// If name is '__proto__', and Object.defineProperty is available, define __proto__ as an own property on target
var setProperty = function setProperty(target, options) {
        if (defineProperty && options.name === '__proto__') {
                defineProperty(target, options.name, {
                        enumerable: true,
                        configurable: true,
                        value: options.newValue,
                        writable: true
                });
        } else {
                target[options.name] = options.newValue;
        }
};

// Return undefined instead of __proto__ if '__proto__' is not an own property
var getProperty = function getProperty(obj, name) {
        if (name === '__proto__') {
                if (!hasOwn.call(obj, name)) {
                        return void 0;
                } else if (gOPD) {
                        // In early versions of node, obj['__proto__'] is buggy when obj has
                        // __proto__ as an own property. Object.getOwnPropertyDescriptor() works.
                        return gOPD(obj, name).value;
                }
        }

        return obj[name];
};

module.exports = function extend() {
        var options, name, src, copy, copyIsArray, clone;
        var target = arguments[0];
        var i = 1;
        var length = arguments.length;
        var deep = false;

        // Handle a deep copy situation
        if (typeof target === 'boolean') {
                deep = target;
                target = arguments[1] || {};
                // skip the boolean and the target
                i = 2;
        }
        if (target == null || (typeof target !== 'object' && typeof target !== 'function')) {
                target = {};
        }

        for (; i < length; ++i) {
                options = arguments[i];
                // Only deal with non-null/undefined values
                if (options != null) {
                        // Extend the base object
                        for (name in options) {
                                src = getProperty(target, name);
                                copy = getProperty(options, name);

                                // Prevent never-ending loop
                                if (target !== copy) {
                                        // Recurse if we're merging plain objects or arrays
                                        if (deep && copy && (isPlainObject(copy) || (copyIsArray = isArray(copy)))) {
                                                if (copyIsArray) {
                                                        copyIsArray = false;
                                                        clone = src && isArray(src) ? src : [];
                                                } else {
                                                        clone = src && isPlainObject(src) ? src : {};
                                                }

                                                // Never move original objects, clone them
                                                setProperty(target, { name: name, newValue: extend(deep, clone, copy) });

                                        // Don't bring in undefined values
                                        } else if (typeof copy !== 'undefined') {
                                                setProperty(target, { name: name, newValue: copy });
                                        }
                                }
                        }
                }
        }

        // Return the modified object
        return target;
};