source: node_modules/traverse/test/lib/deep_equal.js

'use strict';

var traverse = require('../../');

function toS(o) {
        return Object.prototype.toString.call(o);
}

module.exports = function (a, b) {
        if (arguments.length !== 2) {
                throw new Error('deepEqual requires exactly two objects to compare against');
        }

        var equal = true;
        function notEqual() {
                equal = false;
                // this.stop();
                return undefined;
        }

        var node = b;

        traverse(a).forEach(function (y) { // eslint-disable-line consistent-return

                // if (node === undefined || node === null) return notEqual();

                if (!this.isRoot) {
                        /*
            if (!Object.hasOwnProperty.call(node, this.key)) {
                return notEqual();
            }
        */
                        if (typeof node !== 'object') { return notEqual(); }
                        node = node[this.key];
                }

                var x = node;

                this.post(function () {
                        node = x;
                });

                if (this.circular) {
                        if (traverse(b).get(this.circular.path) !== x) { notEqual(); }
                } else if (typeof x !== typeof y) {
                        notEqual();
                } else if (x === null || y === null || x === undefined || y === undefined) {
                        if (x !== y) { notEqual(); }
                } else if (x.__proto__ !== y.__proto__) {
                        notEqual();
                } else if (x === y) {
                        // nop
                } else if (typeof x === 'function') {
                        if (x instanceof RegExp) {
                                // both regexps on account of the __proto__ check
                                if (String(x) !== String(y)) { notEqual(); }
                        } else if (x !== y) { notEqual(); }
                } else if (typeof x === 'object') {
                        if (toS(y) === '[object Arguments]'
            || toS(x) === '[object Arguments]') {
                                if (toS(x) !== toS(y)) {
                                        notEqual();
                                }
                        } else if (toS(y) === '[object RegExp]'
            || toS(x) === '[object RegExp]') {
                                if (!x || !y || x.toString() !== y.toString()) { notEqual(); }
                        } else if (x instanceof Date || y instanceof Date) {
                                if (!(x instanceof Date) || !(y instanceof Date)
                || x.getTime() !== y.getTime()) {
                                        notEqual();
                                }
                        } else {
                                var kx = Object.keys(x);
                                var ky = Object.keys(y);
                                if (kx.length !== ky.length) { return notEqual(); }
                                for (var i = 0; i < kx.length; i++) {
                                        var k = kx[i];
                                        if (!Object.hasOwnProperty.call(y, k)) {
                                                notEqual();
                                        }
                                }
                        }
                }
        });

        return equal;
};