thoughts/node_modules/mongoose/lib/schema/objectid.js

/*!
 * Module dependencies.
 */

var SchemaType = require('../schematype')
  , CastError = SchemaType.CastError
  , driver = global.MONGOOSE_DRIVER_PATH || './../drivers/node-mongodb-native'
  , oid = require('../types/objectid')
  , utils = require('../utils')
  , Document

/**
 * ObjectId SchemaType constructor.
 *
 * @param {String} key
 * @param {Object} options
 * @inherits SchemaType
 * @api private
 */

function ObjectId (key, options) {
  SchemaType.call(this, key, options, 'ObjectID');
};

/*!
 * Inherits from SchemaType.
 */

ObjectId.prototype.__proto__ = SchemaType.prototype;

/**
 * Adds an auto-generated ObjectId default if turnOn is true.
 * @param {Boolean} turnOn auto generated ObjectId defaults
 * @api public
 * @return {SchemaType} this
 */

ObjectId.prototype.auto = function (turnOn) {
  if (turnOn) {
    this.default(defaultId);
    this.set(resetId)
  }

  return this;
};

/**
 * Check required
 *
 * @api private
 */

ObjectId.prototype.checkRequired = function checkRequired (value, doc) {
  if (SchemaType._isRef(this, value, doc, true)) {
    return null != value;
  } else {
    return value instanceof oid;
  }
};

/**
 * Casts to ObjectId
 *
 * @param {Object} value
 * @param {Object} doc
 * @param {Boolean} init whether this is an initialization cast
 * @api private
 */

ObjectId.prototype.cast = function (value, doc, init) {
  if (SchemaType._isRef(this, value, doc, init)) {
    // wait! we may need to cast this to a document

    if (null == value) {
      return value;
    }

    // lazy load
    Document || (Document = require('./../document'));

    if (value instanceof Document) {
      value.$__.wasPopulated = true;
      return value;
    }

    // setting a populated path
    if (value instanceof oid) {
      return value;
    } else if (Buffer.isBuffer(value) || !utils.isObject(value)) {
      throw new CastError('ObjectId', value, this.path);
    }

    // Handle the case where user directly sets a populated
    // path to a plain object; cast to the Model used in
    // the population query.
    var path = doc.$__fullPath(this.path);
    var owner = doc.ownerDocument ? doc.ownerDocument() : doc;
    var pop = owner.populated(path, true);
    var ret = new pop.options.model(value);
    ret.$__.wasPopulated = true;
    return ret;
  }

  if (value === null) return value;

  if (value instanceof oid)
    return value;

  if (value._id && value._id instanceof oid)
    return value._id;

  if (value.toString) {
    try {
      return oid.fromString(value.toString());
    } catch (err) {
      throw new CastError('ObjectId', value, this.path);
    }
  }

  throw new CastError('ObjectId', value, this.path);
};

/*!
 * ignore
 */

function handleSingle (val) {
  return this.cast(val);
}

function handleArray (val) {
  var self = this;
  return val.map(function (m) {
    return self.cast(m);
  });
}

ObjectId.prototype.$conditionalHandlers = {
    '$ne': handleSingle
  , '$in': handleArray
  , '$nin': handleArray
  , '$gt': handleSingle
  , '$lt': handleSingle
  , '$gte': handleSingle
  , '$lte': handleSingle
  , '$all': handleArray
};

/**
 * Casts contents for queries.
 *
 * @param {String} $conditional
 * @param {any} [val]
 * @api private
 */

ObjectId.prototype.castForQuery = function ($conditional, val) {
  var handler;
  if (arguments.length === 2) {
    handler = this.$conditionalHandlers[$conditional];
    if (!handler)
      throw new Error("Can't use " + $conditional + " with ObjectId.");
    return handler.call(this, val);
  } else {
    return this.cast($conditional);
  }
};

/*!
 * ignore
 */

function defaultId () {
  return new oid();
};

function resetId (v) {
  this.$__._id = null;
  return v;
}

/*!
 * Module exports.
 */

module.exports = ObjectId;