Q2ma NPM | npm.io

✍️ Introduction

The "query to mongo aggregate" (q2ma in short) is a tool to execute a mongodb paginated query (using find or aggregate) based on URI query parameters using query-to-mongo.

If you need to execute a aggregation query and provide your own aggregation stages (other than pagination related stages) you can simply pass a pipeline option. Otherwise the paginated query is executed using find.

⛹️ Examples

Simple Paginated Query

To run a simple paginated query on a collection (which is internally executed using find):

const { q2ma } = require(q2ma);
const myModel = require("./model");
const queryString = "name=john&age>21&fields=name,age&sort=name,-age&offset=0&limit=10";

await q2ma(myModel, {queryString});

/* 
{
  Result: [
    {
      "_id": "23fr42tv426gv"
      "name": "john 1",
      "age": 25
    },
    {
      "_id": "ryb456ubn56un"
      "name": "john 2",
      "age": 24
    }
  ],
  Total: 10
}
*/

Using query-to-mongo we produce the following from that queryString:

const criteria = {
  name: 'john',
  age: { $gt: 21 }
}
const fields = {
  name: true, age: true
}
const options = {
  sort: { name: 1, age: -1 },
  offset: 10,
  limit: 10
}

Then q2ma will execute the following queries in parallel:

myModel.find(criteria, projects, options)
myModel.find(criteria).count()

Paginated Aggregation Query

To apply pagination on an aggregation query

const { q2ma } = require(q2ma);
const myModel = require("./model");
const queryString = "age>21&fields=_id,names&sort=_id&offset=0&limit=10";
const pipelines = [
  { $group: {
    _id: "age",
    names: { $push: "$name" }
  } }
];

await q2ma(myModel, {queryString, pipelines});

/* 
{
  Result: [
    {
      "age": 24,
      "names": ["john 1"]
    },
    {
      "age": 25,
      "names": ["john 2", "susie"]
    }
  ],
  Total: 10
}
*/

Then q2ma produces and executes the following aggregation query using that queryString and pipelines:

myModel.aggregate([
  { $match: { age: { $gt: 21 } } },
  { $group: {
    _id: "age",
    names: { $push: "$name" }
  } },
  { $facet: {
      total: [{ $group: { _id: "total", sum: { $sum: 1 } } }],
      pagedResult: [{ $sort: { name: 1, age: -1, _id: -1 } }, { $skip: 0 }, { $limit: 10 }, { $project: { _id: 1, names: 1 } }],
  } }
]);

Note that your filters will go into a match stage before your own pipeline stages and the sorting and paging related stages goes last. To change this behavior you could pass {matchPosition: 'END'} in the options.

🚀 Installation

$ npm i q2ma
# or
$ yarn add q2ma

📖 Documentation

q2ma(collection, {options})

Parameter	Format	Description	Required
`collection`	Object	mongo driver collection reference or mongoose model name	✔
`options`	Object	Options is an object like follow: `{ filter, project, options, pipelines, queryString, dateFields, dateFormat, matchPosition }`	❌

`options`

If you have mongodb pipelines aggregation you can use following combination:

{pipelines, queryString, dateFields, dateFormat, matchPosition}

Parameter	Format	Description	Example	Default Value
`pipelines`	Array	---	`[ { $unwind: 'profile.cards' } ]`	---
`queryString`	String	---	`name=john&age>21&fields=name,age&sort=name,-age&offset=10&limit=10`	---
`dateFields`	String Array	---	---	`["createdAt", "modifiedAt", "updatedAt", "removedAt", "deletedAt", "verifiedAt", "confirmedAt", "timestamp"]`
`dateFormat`	String	enum `NUMBER\|DATE`	---	`DATE`
`matchPosition`	String	where do you want to add your custom pipelines before queryString match or after it. enum `START\|END`	---	`START`

If your query is simple and then need some kind of filter and projection like find or findOne you can use following combination:

{filter, project, options, queryString, dateFields, dateFormat}

Parameter	Format	Description	Example	Default Value
`filter`	Object	like input parameter to `find/findOne`	`{name: "Ed", 'profile.card': xx-xxx-xxx}`	---
`project`	Object	like input parameter to `find/findOne`	`{profile: 1, name: 1, transaction: 1}`	---
`options`	Object	like input parameter to `find/findOne`	`{sort: {'profile.phone': -1}, skit: 10}`	---
`queryString`	String	like url string	`name=john&age>21&fields=name,age&sort=name,-age&offset=10&limit=10`	---
`dateFields`	String Array	---	`['timeAt']`	`["createdAt", "modifiedAt", "updatedAt", "removedAt", "deletedAt", "verifiedAt", "confirmedAt", "timestamp"]`
`dateFormat`	String	enum `NUMBER\|DATE`	---	`DATE`