a-sequelize-bug.js

/**
 * This is the example that works. Defining a simple Theme model with a name and author, that's it.
 */

// Set up Sequelize with DB connection
var Sequelize = require('sequelize');
var sequelize = new Sequelize('sidebar_development', 'sidebar', '', {
  host: 'localhost',
  dialect: 'postgres',
  pool: {
    max: 5,
    min: 0,
    idle: 10000
  }
});

// Create the Theme model with a `name` and `author`.
var Theme = sequelize.define('theme', {
  name: {
    type: Sequelize.STRING,
    allowNull: false
  },
  author: {
    type: Sequelize.STRING,
    allowNull: false
  }
});

// Sync the model to the db (CREATE TABLE, etc etc)
Theme.sync({ force: true });

/**
 * Works great. Runs the following SQL on the database:
 * CREATE TABLE IF NOT EXISTS "themes" (
 *  "id"   SERIAL , 
 *  "name" VARCHAR(255) NOT NULL, 
 *  "author" VARCHAR(255) NOT NULL, 
 *  "createdAt" TIMESTAMP WITH TIME ZONE NOT NULL, 
 *  "updatedAt" TIMESTAMP WITH TIME ZONE NOT NULL, 
 *  PRIMARY KEY ("id")
 * );

b-sequelize-bug.js

/**
 * Now, that options hash for each property is repetitive and gross,
 * so let's assign it to a variable and pass that variable in to each property.
 */

var propertyOptions = {
  type: Sequelize.STRING,
  allowNull: false
};

// Then, as you'd expect, pass that variable in as the value of each property key.
var Theme = sequelize.define('theme', {
  name: JSON.parse(JSON.stringify(propertyOptions)),
  author: JSON.parse(JSON.stringify(propertyOptions))
});

// Now, for some reason the next line doesn't work. It syncs a table, yes, but only
// with the "name" property. No author property.
Theme.sync({ force: true });

/**
 * SQL that's ran:
 * CREATE TABLE IF NOT EXISTS "themes" (
 *   "id"   SERIAL , 
 *   "name" VARCHAR(255) NOT NULL, 
 *   "createdAt" TIMESTAMP WITH TIME ZONE NOT NULL, 
 *   "updatedAt" TIMESTAMP WITH TIME ZONE NOT NULL, 
 *   PRIMARY KEY ("id")
 * );
 * 
 * Notice the lack of `author` column?
 */

// To make things weirder, creating and persisting a model with both the `name` and `author`
// defined sets the value of the `author` property as `name` property in the DB.
var theme = Theme.create({
  name: 'Ember (Dark)',
  author: '@cdl'
});

/**
 * SQL that's ran:
 * INSERT INTO "themes" (
 *   "id","name","updatedAt","createdAt"
 * ) VALUES (
 *   DEFAULT,'@cdl','2015-08-16 17:41:29.352 +00:00','2015-08-16 17:41:29.352 +00:00'
 * ) RETURNING *;
 *
 * See: uses the `author` value to fill the `name` column.
 * 
 * 
 * sidebar_development=> SELECT * FROM themes;
 *  id | name |         createdAt          |         updatedAt
 * ----+------+----------------------------+----------------------------
 *   1 | @cdl | 2015-08-16 11:41:29.352-06 | 2015-08-16 11:41:29.352-06
 */
 

var Theme = sequelize.define('theme', {
...   name: JSON.parse(JSON.stringify(propertyOptions)),
...   author: JSON.parse(JSON.stringify(propertyOptions))
... });
TypeError: Converting circular structure to JSON
    at Object.stringify (native)
    at repl:2:23
    at REPLServer.defaultEval (repl.js:132:27)
    at bound (domain.js:254:14)
    at REPLServer.runBound [as eval] (domain.js:267:12)
    at REPLServer.<anonymous> (repl.js:279:12)
    at REPLServer.emit (events.js:107:17)
    at REPLServer.Interface._onLine (readline.js:214:10)
    at REPLServer.Interface._line (readline.js:553:8)
    at REPLServer.Interface._ttyWrite (readline.js:830:14)
    at ReadStream.onkeypress (readline.js:109:10)
    at ReadStream.emit (events.js:110:17)
    at readline.js:1175:14
    at Array.forEach (native)
    at emitKeys (readline.js:993:10)
    at ReadStream.onData (readline.js:910:14)

var propertyOptions = function(type) {
  return {
    type: type,
    allowNull: true
  };
};

var Theme = sequelize.define('theme', {
  name: propertyOptions(Sequelize.STRING),
  author: propertyOptions(Sequelize.STRING)
});

But even better, instead of type as a parameter, use an options parameter that is merged with some default object.