The RxStack QueryFilter

The QueryFilter component helps you build a mongodb like query from http or socket request.

Installation

npm install @rxstack/query-filter --save

Documentation

• Query filter schema
• Equality
• $in, $nin
• $lt, $lte
• $gt, $gte
• $ne
• $or
• $limit
• $skip
• $sort
• Replace original operator
• Replace $or operator

Query filter schema

QueryFilterSchema is used to whitelist properties coming from the request, allow certain operators, sorting, apply transformations, OR queries and sets default limit.

Important: in http requests all query values are strings. They might have to be converted to the right type.

import {QueryFilterSchema, queryFilter} from '@rxstack/query-filter';

export const myQueryFilterSchema: QueryFilterSchema = {
  'properties': {
    'id': {
      'operators': ['$eq', '$ne'],
      'sort': true,
      'transformers': [parseInt],
    },
    'product_title': {
      'property_path': 'title',
      'operators': ['$ne', '$eq'],
      'sort': true
    }
  },
  'allowOrOperator': true,
  'defaultLimit': 10
};

Using with expressjs or socketio:

import {QueryFilterSchema, QueryFilter} from '@rxstack/query-filter';

// GET /messages?id=1&product_title=any&not_listed=any
app.get('/messages', (request: ExpressRequest, response: ExpressResponse, next: NextFunction): void => {
   const result = queryFilter.createQuery(myQueryFilterSchema, req.query);
});

// client side
socket.emit('messages', { 'params': {
  'id': 1,
  'product_title': {'$ne': 'some'},
  'not_listed': 'any'
}});

// server side
socket.on('messages', (args: any, callback: Function) => {
  const result = queryFilter.createQuery(myQueryFilterSchema, args.params);
});


// output: { 'where': {'id': { '$eq': 1 }, 'product_title': { '$ne': 'some' }}, 'limit': 10, 'skip': 0 }

The output will return QueryInterface;

Operators:

Equality

All fields that do not contain special query parameters are compared directly for equality.

ex: GET /messages?id=1

output: {'where': {'id': { '$eq': 1 }}}

$in, $nin

Find all records where the property does ($in) or does not ($nin) match any of the given values.

ex: GET /messages?roomId[$in]=2&roomId[$in]=5

output: {'where': {'roomId': { '$in': [1,5] }}}

$lt, $lte

Find all records where the value is less ($lt) or less and equal ($lte) to a given value.

ex: GET /messages?createdAt[$lt]=1479664146607

output: {'where': {'createdAt': { '$lt': 1479664146607 }}}

$gt, $gte

Find all records where the value is more ($gt) or more and equal ($gte) to a given value.

ex: GET /messages?createdAt[$gt]=1479664146607

output: {'where': {'createdAt': { '$gt': 1479664146607 }}}

$ne

Find all records that do not equal the given property value.

ex: GET /messages?id[$ne]=1

output: {'where': {'id': { '$ne': 1 }}}

$or

Find all records that match any of the given criteria (you'll need to enabled it in the schema allowOrOperator: true).

ex: GET /messages?$or[0][archived][$ne]=true&$or[1][roomId]=2

output: {'where': {'$or': [{'archived': {'$ne': true}}, {'roomId': {'$eq': 2}}]}}

$limit

Parses the query parameter $limit and cast it to integer, it should not exceed the default value set in the schema. If $limit is not defined in the query then default value set in the schema is used.

ex: GET /messages?$limit=2&read=false

output: {'where': {'read': { '$eq': false }}, 'limit': 2}

$skip

Parses the query parameter $skip and cast it to integer. If $skip is not defined in the query then 0 is returned.

ex: GET /messages?$limit=2&$skip=2&read=false

output: {'where': {'read': { '$eq': false }}, 'limit': 2, 'skip': 2}

$sort

If sorting is enabled for a specific field in the schema then a sort object is returned:

ex: /messages?$limit=10&$sort[createdAt]=-1

output: {'limit': 10, 'sort': {'createdAt': -1}}

Replace original operator

In some cases you need to replace the original operator with something db-specific.

Let's assume we need to perform $regex search on a db-field name with mongoose:

ex: /messages?search=something

import {QueryFilterSchema} from '@rxstack/query-filter';

export const customQueryFilter: QueryFilterSchema = {
  'properties': {
    'search': {
      'property_path': 'name',
      'operators': ['$eq'],
      'replace_operators': [['$eq', '$regex']],
      'transformers': [
        (value: any) => new RegExp(`${value}`, 'i')
      ],
      'sort': true
    }
  },
  'allowOrOperator': false,
  'defaultLimit': 25
};

Replace $or operator

In some cases you need to replace the $or operator with something db-specific.

import {QueryFilterSchema} from '@rxstack/query-filter';

export const customQueryFilter: QueryFilterSchema = {
  // ...
  'allowOrOperator': true,
  'replaceOrOperatorWith': Symbor('or'),
};

License

Licensed under the MIT license.