Javascript port of object selector originally in php

gistfile1.txt

/*
 * Copyright (c) 2011 Yahoo! Inc. All rights reserved.
 */

/*jslint nomen: true */

(function () {
    'use strict';

    function mix(target, source){
        var attribute;

        for(attribute in source){
            if(source.hasOwnProperty(attribute)){
                target[attribute] = source[attribute];
            }
        }

        return target
    }

    window.Selector = function Selector(data) {
        var selectorInstance = function () {
            return selectorInstance.__invoke.apply(selectorInstance, arguments);
        };

        if (typeof data === 'string') {
            data = JSON.parse(data);
        }

        mix(selectorInstance, {
            data: data,

            focus: function (path) {
                var pathParts = path.split('.'),
                    data = this.data,
                    self = this;

                pathParts.forEach(function (attribute) {
                    if (!self.isset(data) || !self.isset(data[attribute])) {
                        data = null;
                        return;
                    }

                    data = data[attribute];
                });

                return Selector(data);
            },

            __invoke: function (path, defaultValue) {
                path = this.clearPath(path);

                switch (this.askingFor(path)) {
                case 'list':
                    defaultValue = defaultValue === undefined ? [] : defaultValue;
                    return this.getList(path, defaultValue);
                case 'dictionary':
                    return this.getDictionaryFromPath(path);
                default:
                    return this.getOne(path, defaultValue);
                }
            },

            findOne: function (contextPath, fieldPath, value) {
                var items = this.findAll(contextPath, fieldPath, value);
                return items[0];
            },

            findAll: function (contextPath, fieldPath, value) {
                var contextObjects = this.getAll(contextPath),
                    foundObjects = contextObjects.filter(function (item) {
                        var contextParser = Selector(item),
                            foundValues = contextParser("[" + fieldPath + "]");

                        return foundValues.indexOf(value) > -1;
                    });

                return foundObjects;
            },

            isList: function (data) {
                return data instanceof Array;
            },

            //protected from here
            clearPath: function (path) {
                return path.replace(/\s+/g, '');
            },

            askingFor: function (path) {
                var posFirstChar = 0,
                    posLastChar = path.length - 1;

                if (path.indexOf('[') === posFirstChar && path.indexOf(']') === posLastChar) {
                    return 'list';
                }
                if (path.indexOf('{') === posFirstChar && path.indexOf('}') === posLastChar) {
                    return 'dictionary';
                }

                return 'one';
            },

            getList: function (path, defaultValue) {
                path = path.replace(/\[|\]/g, '');
                return this.getAll(path, defaultValue);
            },

            getDictionaryFromPath: function (path) {
                var keys, values, pathParts;

                path = path.replace(/\{|\}/g, '');
                pathParts = path.split(':');

                keys = pathParts[0];
                values = pathParts[1];
                return this.getDictionary(keys, values);
            },

            getOne: function (path, defaultValue) {
                var results = this.getAll(path);

                return results[0] !== undefined ? results[0] : defaultValue;
            },

            getAll: function (path, defaultValue) {
                var self = this,
                    orToken = '|',
                    possiblePaths = path.split(orToken),
                    result,
                    possiblePath;

                defaultValue = defaultValue !== undefined ? defaultValue : [];

                possiblePaths.forEach(function (possiblePath) {
                    if (result !== undefined) { return; }
                    result = self.getAllFromPath(possiblePath);
                });

                if (result !== undefined) {
                    return result;
                }

                return defaultValue;
            },

            getAllFromPath: function (path) {
                var self = this,
                    pathParts = path.split('.'),
                    results = [],
                    data = this.data;

                pathParts.forEach(function (attribute) {
                    if (data === undefined) { return; }
                    results = data = self.getAllWithAttribute(data, attribute);
                });

                return results.length === 0 ? undefined : results;
            },

            getAllWithAttribute: function (data, attribute) {
                var results = [],
                    self = this;
                data = data instanceof Array ? data : [data];

                data.forEach(function (item) {
                    if (!self.isset(item)) { return; }
                    if (!self.isset(item[attribute])) { return; }

                    if (self.isList(item[attribute])) {
                        results = results.concat(item[attribute]);
                    } else {
                        results.push(item[attribute]);
                    }
                });

                return results;
            },

            isset: function (data) {
                return data !== undefined && data !== null;
            },

            getDictionary: function (keysPath, valuesPath) {
                var keys = this.getAll(keysPath),
                    values = this.getAll(valuesPath, []),
                    result = {};

                if (!keys || !(keys instanceof Array) || !keys.length) {
                    return {};
                }

                keys.forEach(function (key, position) {
                    result[key] = values[position] === undefined ? null : values[position];
                });

                return result;
            }
        });

        return selectorInstance;
    };
})();