iridium
Version:
A custom lightweight ORM for MongoDB designed for power-users
152 lines (150 loc) • 7.31 kB
JavaScript
var Bluebird = require('bluebird');
/**
* An Iridium collection cursor which allows the itteration through documents
* in the collection, automatically wrapping them in the correct instance type.
*
* @param TDocument The interface representing the collection's documents
* @param TInstance The interface or class used to represent the wrapped documents.
*/
var Cursor = (function () {
/**
* Creates a new Iridium cursor which wraps a MongoDB cursor object
* @param {Model} model The Iridium model that this cursor belongs to
* @param {Object} conditions The conditions that resulte in this cursor being created
* @param {MongoDB.Cursor} cursor The MongoDB native cursor object to be wrapped
* @constructor
*/
function Cursor(model, conditions, cursor) {
this.model = model;
this.conditions = conditions;
this.cursor = cursor;
}
/**
* Counts the number of documents which are matched by this cursor
* @param {function(Error, Number)} callback A callback which is triggered when the result is available
* @return {Promise<number>} A promise which will resolve with the number of documents matched by this cursor
*/
Cursor.prototype.count = function (callback) {
var _this = this;
return new Bluebird(function (resolve, reject) {
_this.cursor.count(true, function (err, count) {
if (err)
return reject(err);
return resolve(count);
});
}).nodeify(callback);
};
/**
* Runs the specified handler over each instance in the query results
* @param {function(Instance)} handler The handler which is triggered for each element in the query
* @param {function(Error)} callback A callback which is triggered when all operations have been dispatched
* @return {Promise} A promise which is resolved when all operations have been dispatched
*/
Cursor.prototype.forEach = function (handler, callback) {
var _this = this;
var helpers = this.model.helpers;
return new Bluebird(function (resolve, reject) {
_this.cursor.forEach(function (item) {
_this.model.handlers.documentReceived(_this.conditions, item, function () { return helpers.wrapDocument.apply(helpers, arguments); }).then(handler);
}, function (err) {
if (err)
return reject(err);
return resolve(null);
});
}).nodeify(callback);
};
/**
* Runs the specified transform over each instance in the query results and returns the resulting transformed objects
* @param {function(Instance): TResult} transform A handler which is used to transform the result objects
* @param {function(Error, TResult[])} callback A callback which is triggered when the transformations are completed
* @return {Promise<TResult[]>} A promise which is fulfilled with the results of the transformations
*/
Cursor.prototype.map = function (transform, callback) {
var _this = this;
var helpers = this.model.helpers;
return new Bluebird(function (resolve, reject) {
var promises = [];
_this.cursor.forEach(function (item) {
promises.push(_this.model.handlers.documentReceived(_this.conditions, item, function () { return helpers.wrapDocument.apply(helpers, arguments); })
.then(transform));
}, function (err) {
if (err)
return reject(err);
return resolve(Bluebird.all(promises));
});
}).nodeify(callback);
};
/**
* Retrieves all matching instances and returns them in an array
* @param {function(Error, TInstance[])} callback A callback which is triggered with the resulting instances
* @return {Promise<TInstance[]>} A promise which resolves with the instances returned by the query
*/
Cursor.prototype.toArray = function (callback) {
var _this = this;
var helpers = this.model.helpers;
return new Bluebird(function (resolve, reject) {
_this.cursor.toArray(function (err, results) {
if (err)
return reject(err);
return resolve(results);
});
}).map(function (document) {
return _this.model.handlers.documentReceived(_this.conditions, document, function () { return helpers.wrapDocument.apply(helpers, arguments); });
}).nodeify(callback);
};
/**
* Retrieves the next item in the results list
* @param {function(Error, TInstance)} callback A callback which is triggered when the next item becomes available
* @return {Promise<TInstance>} A promise which is resolved with the next item
*/
Cursor.prototype.next = function (callback) {
var _this = this;
return new Bluebird(function (resolve, reject) {
_this.cursor.next(function (err, result) {
if (err)
return reject(err);
return resolve(result);
});
}).then(function (document) {
if (!document)
return Bluebird.resolve(null);
return _this.model.handlers.documentReceived(_this.conditions, document, function (document, isNew, isPartial) { return _this.model.helpers.wrapDocument(document, isNew, isPartial); });
}).nodeify(callback);
};
/**
* Returns a new cursor which behaves the same as this one did before any results were retrieved
* @return {Cursor} The new cursor which starts at the beginning of the results
*/
Cursor.prototype.rewind = function () {
this.cursor.rewind();
return this;
};
/**
* Returns a new cursor which sorts its results by the given index expression
* @param {model.IndexSpecification} sortExpression The index expression dictating the sort order and direction to use
* @return {Cursor} The new cursor which sorts its results by the sortExpression
*/
Cursor.prototype.sort = function (sortExpression) {
return new Cursor(this.model, this.conditions, this.cursor.sort(sortExpression));
};
/**
* Returns a new cursor which limits the number of returned results
* @param {Number} limit The maximum number of results to return
* @return {Cursor} The new cursor which will return a maximum number of results
*/
Cursor.prototype.limit = function (limit) {
return new Cursor(this.model, this.conditions, this.cursor.limit(limit));
};
/**
* Returns a new cursor which skips a number of results before it begins
* returning any.
* @param {Number} skip The number of results to skip before the cursor beings returning
* @return {Cursor} The new cursor which skips a number of results
*/
Cursor.prototype.skip = function (skip) {
return new Cursor(this.model, this.conditions, this.cursor.skip(skip));
};
return Cursor;
})();
exports.Cursor = Cursor;
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