PostgreSQL

Let's say the name of the new datatype is pg_new_type in the postgres database. That name has to be mapped to DataTypes.NEWTYPE. Additionally, it is required to create a child postgres-specific datatype.

// myproject/lib/sequelize-additions.js
module.exports = function sequelizeAdditions(Sequelize) {
  DataTypes = Sequelize.DataTypes
  /*
   * Create new types
   */
  ...
  /*
   * Map new types
   */
  // Mandatory, map postgres datatype name
  DataTypes.NEWTYPE.types.postgres = ['pg_new_type']
  // Mandatory, create a postgres-specific child datatype with its own parse
  // method. The parser will be dynamically mapped to the OID of pg_new_type.
  PgTypes = DataTypes.postgres
  PgTypes.NEWTYPE = function NEWTYPE() {
    if (!(this instanceof PgTypes.NEWTYPE)) return new PgTypes.NEWTYPE();
    DataTypes.NEWTYPE.apply(this, arguments);
  }
  inherits(PgTypes.NEWTYPE, DataTypes.NEWTYPE);
  // Mandatory, create, override or reassign a postgres-specific parser
  //PgTypes.NEWTYPE.parse = value => value;
  PgTypes.NEWTYPE.parse = DataTypes.NEWTYPE.parse;
  // Optional, add or override methods of the postgres-specific datatype
  // like toSql, escape, validate, _stringify, _sanitize...
}

Ranges

After a new range type has been defined in postgres, it is trivial to add it to Sequelize.

In this example the name of the postgres range type is newtype_range and the name of the underlying postgres datatype is pg_new_type. The key of subtypes and castTypes is the key of the Sequelize datatype DataTypes.NEWTYPE.key, in lower case.

// myproject/lib/sequelize-additions.js
module.exports = function sequelizeAdditions(Sequelize) {
  DataTypes = Sequelize.DataTypes
  /*
   * Create new types
   */
  ...
  /*
   * Map new types
   */
  ...
  /*
   * Add suport for ranges
   */
  // Add postgresql range, newtype comes from DataType.NEWTYPE.key in lower case
  DataTypes.RANGE.types.postgres.subtypes.newtype = 'newtype_range';
  DataTypes.RANGE.types.postgres.castTypes.newtype = 'pg_new_type';
}

The new range can be used in model definitions as Sequelize.RANGE(Sequelize.NEWTYPE) or DataTypes.RANGE(DataTypes.NEWTYPE).