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feat(aggregation): Add first aggregation functionallity
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| Original file line number | Diff line number | Diff line change |
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| /** | ||
| * @file Cursor.js - based on Monglo#Cursor ({@link https://github.com/Monglo}) by Christian Sullivan <cs@euforic.co> | Copyright (c) 2012 | ||
| * @version 1.0.0 | ||
| * | ||
| * @author Eduardo Astolfi <eduardo.astolfi91@gmail.com> | ||
| * @copyright 2016 Eduardo Astolfi <eduardo.astolfi91@gmail.com> | ||
| * @license MIT Licensed | ||
| */ | ||
|
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| var _ = require("lodash"), | ||
| Logger = require("jsw-logger"); | ||
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| var logger = null; | ||
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| var stages = { | ||
| '$project': false, | ||
| '$match': false, | ||
| '$redact': false, | ||
| '$limit': false, | ||
| '$skip': false, | ||
| '$unwind': false, | ||
| '$group': true, | ||
| '$sample': false, | ||
| '$sort': false, | ||
| '$geoNear': false, | ||
| '$lookup': false, | ||
| '$out': false, | ||
| '$indexStats': false | ||
| }; | ||
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| var group_operators = { | ||
| $sum: function(documents, new_id, new_field, value, isCount) { | ||
| var new_docs = {}; | ||
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| for (let i = 0; i < documents.length; i++) { | ||
| let doc = documents[i]; | ||
| let val = value; | ||
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| if (!isCount) { | ||
| val = doc[value.substr(1, value.length)] || 0; | ||
| } | ||
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| if (_.hasIn(doc, new_id)) { | ||
| let _id = doc[new_id]; | ||
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| if (!_.hasIn(new_docs, _id)) { | ||
| new_docs[_id] = { | ||
| _id: _id, | ||
| [new_field]: _.toNumber(val) | ||
| }; | ||
| } else { | ||
| new_docs[_id][new_field] += _.toNumber(val); | ||
| } | ||
| } | ||
| } | ||
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| return new_docs; | ||
| }, | ||
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| $avg: function(documents, new_id, new_field, value, isCount) { | ||
| var new_docs = {}; | ||
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| for (let i = 0; i < documents.length; i++) { | ||
| let doc = documents[i]; | ||
| let val = value; | ||
|
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| if (!isCount) { | ||
| val = doc[value.substr(1, value.length)] || 0; | ||
| } | ||
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| if (_.hasIn(doc, new_id) || _.isNull(new_id)) { | ||
| let _id = doc[new_id] || null; | ||
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| if (!_.hasIn(new_docs, _id)) { | ||
| new_docs[_id] = { | ||
| _id: _id, | ||
| [new_field]: _.toNumber(val), | ||
| __COUNT__: 1 | ||
| }; | ||
| } else { | ||
| new_docs[_id][new_field] += _.toNumber(val); | ||
| new_docs[_id].__COUNT__++; | ||
| } | ||
| } | ||
| } | ||
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| for (let key in new_docs) { | ||
| new_docs[key][new_field] = new_docs[key][new_field] / new_docs[key].__COUNT__; | ||
| delete new_docs[key].__COUNT__; | ||
| } | ||
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| return new_docs; | ||
| } | ||
| }; | ||
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| var do_single_group = function(group_id, group_stage, documents) { | ||
| // var operators = {}; | ||
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| let docs = {}; | ||
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| for (let field in group_stage) { | ||
| if (field !== '_id') { | ||
| // handle group field | ||
| // let group_key = key; | ||
| let group_field = group_stage[field]; | ||
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| for (let key in group_field) { | ||
| if (!_.hasIn(group_operators, key)) logger.throw(`Unknown accumulator operator "${key}" for group stage`); | ||
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| // loop through all documents | ||
| // var new_docs = {}; | ||
| // for (let i = 0; i < documents.length; i++) { | ||
| // let doc = documents[i]; | ||
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| // if (_.hasIn(doc, group_id)) { | ||
| // let _id = doc[group_id]; | ||
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| // if (!_.hasIn(new_docs, _id)) { | ||
| // new_docs[_id] = { | ||
| // _id: _id, | ||
| // [new_field]: value | ||
| // }; | ||
| // } else { | ||
| // new_docs[_id][new_field] += value; | ||
| // } | ||
| // } | ||
| // } | ||
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| // if (!_.hasIn(operators, key)) operators[key] = []; | ||
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| // operators[key].push({ | ||
| // new_field: field, | ||
| // value: group_field[key] | ||
| // }); | ||
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| let count = true; | ||
| if (_.isString(group_field[key])) { | ||
| if (group_field[key].substr(0, 1) !== '$') logger.throw("Field names references in a right side assignement must be preceded by '$'"); | ||
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| if (!_.isFinite(_.toNumber(group_field[key]))) { | ||
| count = false; | ||
| } | ||
| } | ||
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| let operator = group_operators[key]; | ||
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| _.merge(docs, operator(documents, group_id, field, group_field[key], count)); | ||
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| break; | ||
| } | ||
| } | ||
| } | ||
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| return _.values(docs); | ||
| }; | ||
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| var do_complex_group = function() { | ||
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| }; | ||
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| var do_group = function(documents, group_stage) { | ||
| if (!_.hasIn(group_stage, '_id')) logger.throw('The field "_id" is required in the "$group" stage'); | ||
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| let new_id = group_stage['_id']; | ||
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| if (_.isPlainObject(new_id)) { | ||
| // complex_id | ||
| // do_complex_group(); | ||
| } else { | ||
| // single_id | ||
| return do_single_group(new_id, group_stage, documents); | ||
| } | ||
| }; | ||
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| class Aggregation { | ||
| constructor(pipeline) { | ||
| logger = Logger.instance; | ||
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| this.pipeline = pipeline; | ||
| } | ||
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| aggregate(collection) { | ||
| for (let i = 0; i < this.pipeline.length; i++) { | ||
| let stage = this.pipeline[i]; | ||
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| for (let key in stage) { | ||
| switch (key) { | ||
| case '$group': | ||
| return do_group(collection.docs, stage[key]); | ||
| } | ||
| } | ||
| } | ||
| } | ||
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| validStage(stage) { | ||
| if (!_.hasIn(stages, stage)) return logger.throw(`Unknown stage "${stage}"`); | ||
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| if (stages[stage] === false) return logger.throw(`Unsupported stage "${stage}"`); | ||
|
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| return true; | ||
| } | ||
| } | ||
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| module.exports = Aggregation; |
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