N-params-processor NPM

n-params-processor

Node.js parameters parser/validator and mongodb/sequelize query/data-object builder.

Installation

$ npm i n-params-processor

Example of usage

const MongooseQB  = require('n-params-processor').MongooseQB
const DataBuilder = require('n-params-processor').DataBuilder

/* Request:
- GET /api/users?role=user&fields=firstName%20lastName&users[]=1,2,3&page=5&count=10&sortBy=firstName
*/
exports.getUsers = async (req, res, next) => {
  try {
    const ALLOWED_FIELDS = 'id firstName lastName age'
    const DEFAULT_FIELDS = 'id firstName lastName'
    let queryBuilder = new MongooseQB({
      source: req.query
    })
    queryBuilder.parseString({ name: 'role', az: 'userRole', required: true })
    queryBuilder.parseArray({ name: 'users', az: 'userId', itemType: 'int', op: 'in' })
    queryBuilder.parseFields({ allowed: ALLOWED_FIELDS, def: DEFAULT_FIELDS })
    queryBuilder.parsePagination()
    queryBuilder.parseSorting()

    let query = queryBuilder.build()
    /* query is an object: {
      filter: {
        userRole: { $eq: 'user' },
        userId: { $in: [1, 2, 3] }
      },
      fields: 'firstName lastName',
      pagination: { page: 5, count: 10 },
      sorting: { sortBy: 'firstName', sortDirection: 'asc' }
    }*/
    let users = await usersSrvc.getUsers(query)
    res.send(users)
  } catch (err) {
    next(err)
  }
}

/* Request:
- POST /api/users
  BODY: {
    firstName: 'John',
    age: '25',
    roles: ['user']
  }
*/
exports.createUser = async (req, res, next) => {
  try {
    let dataBuilder = new DataBuilder({
      source: req.body,
      data: { creator: req.user.userId }
    })
    dataBuilder.parseString({ name: 'firstName', max: 10, required: true })
    dataBuilder.parseString({ name: 'lastName', max: 20, def: 'not prodived' })
    dataBuilder.parseInt({ name: 'age', min: 18, max: 55, required: true })
    dataBuilder.parseArray({ name: 'roles', allowed: ['user', 'admin', 'owner'], itemType: 'string' })

    let userData = dataBuilder.build()
    /* userData is an object: {
      creator: '58ea5b07973ab04f88def3fa', // base value
      firstName: 'John',
      lastName: 'not prodived', // default value is used
      age: 25, // age converted to Number
      roles: ['user']
    }*/
    let user = await usersSrvc.createUser(userData)
    res.send(user)
  } catch (err) {
    next(err)
  }
}

API

consts

The constants objects. OPERATORS field contains all valid query operators.

ParamsProcessorError

The error object that package throws in the case of error.

BaseBuilder API

This is a base builder class, an object of this class shouldn't be used directly. Instead of this inherit of QueryBuilder or DataBuilder must be used.

constructor(params)

params is an object with the following fields:
- source: base source object, can be req.body for example. Parsers will use this source if custom is not provided, optional.
- data: base data object, can include some common fields: { currentUser: req.user } for example, optional.

parseType(params)

Common parameters of parseType method.

params is an object with the following fields:
- source: source object, if not provided instance.source is used, optional.
- name: parameter name.
- az: new name, optional.
- def: default value, is used when parameter value is nil, optional.
- required: indicates that parameter value is mandatory, optional.
- to: object that should be used to save parsed value, optional.

parseString(params)

Parses, converts to String and validates parameter value.

params is an object with the same fields as for parseType, except:
- min: the lowest possible string length, optional.
- max: the largest possible string length, optional.
- allowed: validates that allowed array includes parameter value, optional.

parseDate(params, output)

Parses, converts to Date and validates parameter value.

params is an object with the same fields as for parseType, except:
- format: is date time format, if not provided monent.defaultFormat is used, optional.
- formatRes: is a result object format, can be Date or format string, optional.
- min: the lowest possible date, optional.
- max: the largest possible date, optional.

parseJson(params)

Parses, converts to JSON and validates parameter value.

params is an object with the same fields as for parseType.

parseBool(params)

Parses, converts to Boolean and validates parameter value.

params is an object with the same fields as for parseType.

parseNumber(params)

Parses, converts to Number and validates parameter value.

params is an object with the same fields as for parseType, except:
- min: the lowest possible value, optional.
- max: the largest possible value, optional.
- allowed: validates that allowed array includes parameter value, optional.

parseInt(params)

Parses, converts to IntegerNumber and validates parameter.

params is an object with the same fields as for parseNumber.

parseFloat(params)

Parses, converts to FloatNumber and validates parameter.

params is an object with the same fields as for parseNumber.

parseRegexp(params)

Parses and validates parameter.

params is an object with the same fields as for parseType, except:
- pattern: Regular expression that should be used to test parameter value.

parseObjectId(params)

Parses, converts to ObjectId and validates parameter.

params is an object with the same fields as for parseType.

parseEmail(params)

Parses and validates email parameter.

params is an object with the same fields as for parseType.

parseCustom(params)

Parses and validates parameters using custom handler.

params is an object with the same fields as for parseType, except:
- handler: the function that accepts value and returns some result, required.

parseArray(params)

Parses, converts to itemType and validates parameter.

params is an object with the same fields as for parseType, except:
- itemType the array item type (on of the registered parser types: Int, String, Bool, etc).
- itemHandler the handler for custom item type.
- allowed: validates that parameter value is subset of allowed array, optional.

DataBuilder API

Should be used for creating a plain data object, to use in create and update operations.

constructor(params)

params is an object with the same fields as for BaseBuilder.constructor.

build()

Returns a final data object.

QueryBuilder (MongooseQueryBuilder, SequelizeQueryBuilder) API

Should be used for generating database query.

constructor(params)

params is an object with the same fields as for BaseBuilder.constructor, except:
- filter: base filter, can include some common parameters, optional.

parseFields(params)

Parses, converts and validates fields parameter. Validated parameter value must be space separated string of values.

params is an object with the following fields:
- source: source object, if not defined instance.source is used.
- fieldsName: the name of fields parameter, if not provided fields is used, optional.
- allowed: space separated string of allowed fields.
- def: space separated string of default fields.

parsePagination(params)

Parses, converts and validates pagination parameters. By default pagination object is null.

params is an object with the following fields:
- source: source object, if not defined instance.source is used.
- pageName: the name of page parameter, if not provided page is used, optional.
- countName: the name of count parameter, if not provided count is used, optional.

parseSorting(params)

Parses, converts and validates sorting parameters. By default sorting object is null.

params is an object with the following fields:
- source: source object, if not defined instance.source is used.
- sortByName: the name of sortBy parameter, if not provided sortBy is used, optional.
- sortDirName: the name of sortDirection parameter, if not provided sortDirection is used, optional.