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Simple server side pagination module for mongodb
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'use strict'; | |
/** | |
* Paginator | |
* | |
* The MIT License (MIT) | |
* Copyright (c) 2014 Shekhar R. Thawali<shekhar@leftshift.io> | |
* | |
* Permission is hereby granted, free of charge, to any person obtaining a copy | |
* of this software and associated documentation files (the "Software"), to deal | |
* in the Software without restriction, including without limitation the rights | |
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
* copies of the Software, and to permit persons to whom the Software is | |
* furnished to do so, subject to the following conditions: | |
* | |
* The above copyright notice and this permission notice shall be included in | |
* all copies or substantial portions of the Software. | |
* | |
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | |
* THE SOFTWARE. | |
* | |
*/ | |
exports.paginator = function(db) { | |
if (!db) { | |
throw new Error('You are not connected to database server. {db} is missing.'); | |
} | |
/** | |
* Options | |
*/ | |
this.db = db; | |
this.collection = null; | |
this.query = {}; | |
this.sort = false; | |
this.current = 1; | |
this.recordPerPage = 50; | |
/** | |
* Records count && total records | |
*/ | |
this.recordCount = 0; | |
this.totalRecords = 0; | |
/** | |
* Calculate records data | |
* @return {object} paginator object with records | |
*/ | |
var calculatePagedData = function(that, records) { | |
var totalResult = that.totalRecords; | |
var recordPerPage = that.recordPerPage; | |
var current = that.current; | |
var pageCount; | |
/** | |
* Basic result object | |
* @type {Object} | |
*/ | |
var result = { | |
current: current, | |
previous: null, | |
next: null, | |
first: null, | |
last: null, | |
totalResult: totalResult, | |
pageCount: null, | |
records: records | |
}; | |
/** | |
* Return if recordPerPage negative | |
*/ | |
if (recordPerPage <= 0) { | |
return result; | |
} | |
/** | |
* Calculate page count | |
* @type {Number} | |
*/ | |
pageCount = Math.ceil(totalResult / recordPerPage); | |
result.pageCount = pageCount; | |
/** | |
* Return if page count is less than 2 | |
*/ | |
if (pageCount < 2) { | |
return result; | |
} | |
/** | |
* Update current value if current > pageCount | |
*/ | |
if (current > pageCount) { | |
current = pageCount; | |
result.current = current; | |
} | |
/** | |
* Set first and previous | |
*/ | |
if (current > 1) { | |
result.first = 1; | |
result.previous = current - 1; | |
} | |
/** | |
* Set last and next | |
*/ | |
if (current < pageCount) { | |
result.last = pageCount; | |
result.next = current + 1; | |
} | |
/** | |
* Return final result object | |
*/ | |
return result; | |
} | |
/** | |
* Get records with paginator object | |
* @param {object} options Options object | |
* @param {function} callback Callback function | |
* @return {object} paginator object with records | |
* | |
* Usage: | |
* | |
* var Paginator = require(PATH_OF_PAGINATOR); | |
* var pagination = new Paginator(DATABASE); | |
* | |
* pagination.getPaginatedRecords(OPTIONS, CALLBACK_FUNCTION); | |
* | |
* Options: | |
* { | |
* collection: COLLECTION_NAME, // required | |
* query: QUERY_TO_FETCH_RECORDS // optional | |
* sort: SORTING_ORDER, // optional. Format is {KEY: 1/-1} | |
* current: CURRENT_PAGE_NUMBER, // default 1 | |
* recordPerPage: RECORD_PER_PAGE // default 50, | |
* totalResult: TOTAL_RESULTS | |
* } | |
* | |
* Callback Function: | |
* function(err, paginatedData); | |
* | |
* Response: | |
* { | |
* current: CURRENT_PAGE_NUMBER, | |
* previous: PRIVIOUS_PAGE_NUMBER, | |
* next: NEXT_PAGE_NUMBER, | |
* first: FIRST_PAGE_NUMBER, | |
* last: LAST_PAGE_NUMBER, | |
* totalResult: TOTAL_RECORDS_COUNT, | |
* pageCount: TOTAL_PAGES_COUNT, | |
* records: RECORDS_ARRAY | |
* } | |
* | |
* Example: | |
* | |
* var Paginator = require(./paginator); | |
* var pagination = new Paginator(db); | |
* | |
* pagination.getPaginatedRecords({ | |
* collection: 'users', | |
* recordPerPage: 10 | |
* }, function(err, data) { | |
* if(err) { | |
* return next(err); | |
* } | |
* | |
* // Do stuff with data object | |
* | |
* }); | |
*/ | |
this.getPaginatedRecords = function(options, callback) { | |
var that = this; | |
/** | |
* if callback is passed | |
* @type {function} | |
*/ | |
if (typeof options === 'function') { | |
callback = options; | |
} | |
/** | |
* Check for collection exist | |
*/ | |
if (options.collection) { | |
this.collection = options.collection; | |
} | |
if (!options.collection) { | |
return callback(new Error('Collection name is required. {collection} is missing from options')); | |
} | |
if (options.query) { | |
this.query = options.query; | |
} | |
if (options.sort) { | |
this.sort = options.sort; | |
} | |
if (options.current) { | |
this.current = options.current; | |
} | |
if (options.recordPerPage) { | |
this.recordPerPage = options.recordPerPage; | |
} | |
if (options.totalResult) { | |
this.totalRecords = options.totalResult; | |
} | |
/** | |
* Collection object | |
* @type {object} | |
*/ | |
var collection = this.db[this.collection]; | |
/** | |
* Prepare base db object | |
* @type {object} | |
*/ | |
var base = collection | |
.find(this.query) | |
.limit(this.recordPerPage) | |
.skip(this.skip); | |
/** | |
* If sorting then do sort | |
*/ | |
if (this.sort) { | |
base.sort(this.sort); | |
} | |
/** | |
* Get records for query | |
* @param {object} err Error object | |
* @param {object} records Records for query | |
* @return {object} Paginated object | |
*/ | |
var getRecords = function() { | |
base.toArray(function(err, records) { | |
if (err) { | |
return callback(err); | |
} | |
that.recordCount = records.length; | |
callback(calculatePagedData(that, records)); | |
}); | |
}; | |
if (this.totalResult) { | |
return getRecords(); | |
} else { | |
/** | |
* Get total records count for query | |
* @param {object} err Error object | |
* @param {Number} count Total records count | |
* @return {Number} Total number of records | |
*/ | |
collection.count(this.query, function(err, count) { | |
if (err) { | |
return callback(err); | |
} | |
that.totalRecords = count; | |
getRecords(); | |
}); | |
} | |
}; | |
}; |
👍 this looks hep!
whoa! good job boss
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If total records count is pass in options then skip
collection.count