304 lines
10 KiB
JavaScript
304 lines
10 KiB
JavaScript
/**
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* Dependencies
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*/
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var i8n = require('inflection');
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var defineScope = require('./scope.js').defineScope;
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var ModelBaseClass = require('./model.js');
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module.exports = Relation;
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function Relation() {
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}
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Relation.relationNameFor = function relationNameFor(foreignKey) {
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for (var rel in this.relations) {
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if (this.relations[rel].type === 'belongsTo' && this.relations[rel].keyFrom === foreignKey) {
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return rel;
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}
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}
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};
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/**
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* Declare hasMany relation
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*
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* @param {Relation} anotherClass - class to has many
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* @param {Object} params - configuration {as:, foreignKey:}
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* @example `User.hasMany(Post, {as: 'posts', foreignKey: 'authorId'});`
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*/
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Relation.hasMany = function hasMany(anotherClass, params) {
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var thisClass = this, thisClassName = this.modelName;
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params = params || {};
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if (typeof anotherClass === 'string') {
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params.as = anotherClass;
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if (params.model) {
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anotherClass = params.model;
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} else {
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var anotherClassName = i8n.singularize(anotherClass).toLowerCase();
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for(var name in this.dataSource.models) {
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if (name.toLowerCase() === anotherClassName) {
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anotherClass = this.dataSource.models[name];
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}
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}
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}
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}
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var methodName = params.as || i8n.camelize(anotherClass.pluralModelName, true);
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var fk = params.foreignKey || i8n.camelize(thisClassName + '_id', true);
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this.relations[methodName] = {
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type: 'hasMany',
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keyFrom: 'id',
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keyTo: fk,
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modelTo: anotherClass,
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multiple: true
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};
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// each instance of this class should have method named
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// pluralize(anotherClass.modelName)
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// which is actually just anotherClass.all({where: {thisModelNameId: this.id}}, cb);
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var scopeMethods = {
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findById: find,
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destroy: destroy
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};
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if (params.through) {
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var fk2 = i8n.camelize(anotherClass.modelName + '_id', true);
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scopeMethods.create = function create(data, done) {
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if (typeof data !== 'object') {
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done = data;
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data = {};
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}
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if ('function' !== typeof done) {
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done = function() {};
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}
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var self = this;
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var id = this.id;
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anotherClass.create(data, function(err, ac) {
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if (err) return done(err, ac);
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var d = {};
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d[params.through.relationNameFor(fk)] = self;
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d[params.through.relationNameFor(fk2)] = ac;
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params.through.create(d, function(e) {
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if (e) {
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ac.destroy(function() {
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done(e);
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});
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} else {
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done(err, ac);
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}
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});
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});
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};
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scopeMethods.add = function(acInst, done) {
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var data = {};
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var query = {};
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query[fk] = this.id;
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data[params.through.relationNameFor(fk)] = this;
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query[fk2] = acInst.id || acInst;
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data[params.through.relationNameFor(fk2)] = acInst;
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params.through.findOrCreate({where: query}, data, done);
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};
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scopeMethods.remove = function(acInst, done) {
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var self = this;
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var q = {};
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q[fk2] = acInst.id || acInst;
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params.through.findOne({where: q}, function(err, d) {
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if (err) {
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return done(err);
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}
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if (!d) {
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return done();
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}
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d.destroy(done);
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});
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};
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delete scopeMethods.destroy;
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}
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defineScope(this.prototype, params.through || anotherClass, methodName, function () {
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var filter = {};
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filter.where = {};
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filter.where[fk] = this.id;
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if (params.through) {
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filter.collect = i8n.camelize(anotherClass.modelName, true);
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filter.include = filter.collect;
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}
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return filter;
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}, scopeMethods);
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if (!params.through) {
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// obviously, anotherClass should have attribute called `fk`
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anotherClass.dataSource.defineForeignKey(anotherClass.modelName, fk, this.modelName);
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}
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function find(id, cb) {
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anotherClass.findById(id, function (err, inst) {
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if (err) return cb(err);
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if (!inst) return cb(new Error('Not found'));
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if (inst[fk] && inst[fk].toString() == this.id.toString()) {
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cb(null, inst);
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} else {
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cb(new Error('Permission denied'));
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}
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}.bind(this));
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}
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function destroy(id, cb) {
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this.findById(id, function (err, inst) {
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if (err) return cb(err);
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if (inst) {
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inst.destroy(cb);
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} else {
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cb(new Error('Not found'));
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}
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});
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}
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};
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/**
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* Declare belongsTo relation
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*
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* @param {Class} anotherClass - class to belong
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* @param {Object} params - configuration {as: 'propertyName', foreignKey: 'keyName'}
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*
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* **Usage examples**
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* Suppose model Post have a *belongsTo* relationship with User (the author of the post). You could declare it this way:
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* Post.belongsTo(User, {as: 'author', foreignKey: 'userId'});
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*
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* When a post is loaded, you can load the related author with:
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* post.author(function(err, user) {
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* // the user variable is your user object
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* });
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*
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* The related object is cached, so if later you try to get again the author, no additional request will be made.
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* But there is an optional boolean parameter in first position that set whether or not you want to reload the cache:
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* post.author(true, function(err, user) {
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* // The user is reloaded, even if it was already cached.
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* });
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*
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* This optional parameter default value is false, so the related object will be loaded from cache if available.
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*/
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Relation.belongsTo = function (anotherClass, params) {
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params = params || {};
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if ('string' === typeof anotherClass) {
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params.as = anotherClass;
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if (params.model) {
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anotherClass = params.model;
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} else {
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var anotherClassName = anotherClass.toLowerCase();
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for(var name in this.dataSource.models) {
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if (name.toLowerCase() === anotherClassName) {
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anotherClass = this.dataSource.models[name];
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}
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}
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}
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}
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var methodName = params.as || i8n.camelize(anotherClass.modelName, true);
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var fk = params.foreignKey || methodName + 'Id';
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this.relations[methodName] = {
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type: 'belongsTo',
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keyFrom: fk,
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keyTo: 'id',
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modelTo: anotherClass,
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multiple: false
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};
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this.dataSource.defineForeignKey(this.modelName, fk, anotherClass.modelName);
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this.prototype['__finders__'] = this.prototype['__finders__'] || {};
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this.prototype['__finders__'][methodName] = function (id, cb) {
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if (id === null) {
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cb(null, null);
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return;
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}
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anotherClass.findById(id, function (err,inst) {
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if (err) return cb(err);
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if (!inst) return cb(null, null);
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if (inst.id === this[fk]) {
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cb(null, inst);
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} else {
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cb(new Error('Permission denied'));
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}
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}.bind(this));
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};
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this.prototype[methodName] = function (refresh, p) {
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if (arguments.length === 1) {
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p = refresh;
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refresh = false;
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} else if (arguments.length > 2) {
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throw new Error('Method can\'t be called with more than two arguments');
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}
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var self = this;
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var cachedValue;
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if (!refresh && this.__cachedRelations && (typeof this.__cachedRelations[methodName] !== 'undefined')) {
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cachedValue = this.__cachedRelations[methodName];
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}
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if (p instanceof ModelBaseClass) { // acts as setter
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this[fk] = p.id;
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this.__cachedRelations[methodName] = p;
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} else if (typeof p === 'function') { // acts as async getter
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if (typeof cachedValue === 'undefined') {
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this.__finders__[methodName].apply(self, [this[fk], function(err, inst) {
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if (!err) {
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self.__cachedRelations[methodName] = inst;
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}
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p(err, inst);
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}]);
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return this[fk];
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} else {
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p(null, cachedValue);
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return cachedValue;
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}
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} else if (typeof p === 'undefined') { // acts as sync getter
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return this[fk];
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} else { // setter
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this[fk] = p;
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delete this.__cachedRelations[methodName];
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}
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};
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};
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/**
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* Many-to-many relation
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*
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* Post.hasAndBelongsToMany('tags'); creates connection model 'PostTag'
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*/
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Relation.hasAndBelongsToMany = function hasAndBelongsToMany(anotherClass, params) {
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params = params || {};
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var models = this.dataSource.models;
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if ('string' === typeof anotherClass) {
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params.as = anotherClass;
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if (params.model) {
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anotherClass = params.model;
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} else {
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anotherClass = lookupModel(i8n.singularize(anotherClass)) ||
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anotherClass;
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}
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if (typeof anotherClass === 'string') {
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throw new Error('Could not find "' + anotherClass + '" relation for ' + this.modelName);
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}
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}
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if (!params.through) {
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var name1 = this.modelName + anotherClass.modelName;
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var name2 = anotherClass.modelName + this.modelName;
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params.through = lookupModel(name1) || lookupModel(name2) ||
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this.dataSource.define(name1);
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}
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params.through.belongsTo(this);
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params.through.belongsTo(anotherClass);
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this.hasMany(anotherClass, {as: params.as, through: params.through});
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function lookupModel(modelName) {
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var lookupClassName = modelName.toLowerCase();
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for (var name in models) {
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if (name.toLowerCase() === lookupClassName) {
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return models[name];
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}
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}
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}
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};
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