dynamoose/lib/VirtualType.js

Dynamoose is a modeling tool for Amazon's DynamoDB (inspired by Mongoose)

const debug = require('debug')('dynamoose:virtualtype');

/**
 * VirtualType constructor
 *
 * This is what mongoose uses to define virtual attributes via `Schema.prototype.virtual`.
 *
 * ####Example:
 *
 *     let fullname = schema.virtual('fullname');
 *     fullname instanceof mongoose.VirtualType // true
 *
 * @parma {Object} options
 * @api public
 */

function VirtualType (options, name) {
  this.path = name;
  this.options = options || {};
}

/**
 * Defines a getter.
 *
 * ####Example:
 *
 *     let virtual = schema.virtual('fullname');
 *     virtual.get(function () {
 *       return this.name.first + ' ' + this.name.last;
 *     });
 *
 * @param {Function} fn
 * @return {VirtualType} this
 * @api public
 */

VirtualType.prototype.get = function (fn) {
  debug('registering getter for ' + this.path);
  this.getter = fn;
  return this;
};

/**
 * Defines a setter.
 *
 * ####Example:
 *
 *     let virtual = schema.virtual('fullname');
 *     virtual.set(function (v) {
 *       let parts = v.split(' ');
 *       this.name.first = parts[0];
 *       this.name.last = parts[1];
 *     });
 *
 * @param {Function} fn
 * @return {VirtualType} this
 * @api public
 */

VirtualType.prototype.set = function (fn) {
  debug('registering setter for ' + this.path);
  this.setter = fn;
  return this;
};


/**
 * Applies getters and setters to the model
 * @param {Object} model
 * @return {any} the value after applying all getters
 * @api public
 */
VirtualType.prototype.applyVirtuals = function (model) {
    debug('applyVirtuals for %s', this.path);
    let property = {enumerable: true, configurable: true};

    if (this.setter){
      property.set = this.setter;
    }

    if (this.getter){
      property.get = this.getter;
    }

    Object.defineProperty(model, this.path, property);
};

/*!
 * exports
 */

module.exports = VirtualType;