@dialexa/pleco-graphql

Pleco GraphQL

Table of Contents

• Overview
• GraphQL Types
  • Provided Exports
    • Notes
  • Usage

Overview

This library provides GraphQL types that can be used to form your own filter types

GraphQL Types

All the GraphQL types can be found in src/graphql/index.ts. For each GraphQLScalarType (excluding Boolean), which includes ID, Int, String, and Float, we provide a GraphQL type allowing users to provide comparison operations like in, lt, gt, eq, as well as the nesting abilities with AND and OR.

Provided Exports

operation	FilterQuery_Boolean	FilterQuery_ID	FilterQuery_String	FilterQuery_Int	FilterQuery_Float
AND	✔	✔	✔	✔	✔
OR	✔	✔	✔	✔	✔
in	✔	✔	✔	✔	✔
nin	✔	✔	✔	✔	✔
eq	✔	✔	✔	✔	✔
ne	✔	✔	✔	✔	✔
gt			✔	✔	✔
lt			✔	✔	✔
gte			✔	✔	✔
lte			✔	✔	✔
contains			✔

In addition to the 4 FilterQuery_* types, pleco-graphql also provides

• SortDirection: an enum of ASC and DESC
• LimitOffsetPage: an input object with limit and offset
• graphQLTypes which is a string containing the definitions of all the types in SDL.

All these exports were written using what they will appear as in SDL. The javascript objects are:

SDL Name	Javascript Export
FilterQuery_Boolean	GraphQLFilterQueryBoolean
FilterQuery_ID	GraphQLFilterQueryID
FilterQuery_String	GraphQLFilterQueryString
FilterQuery_Int	GraphQLFilterQueryInt
FilterQuery_Float	GraphQLFilterQueryFloat
SortDirection	GraphQLSortDirection
LimitOffsetPage	GraphQLLimitOffsetPage

Notes

• null can be passed to eq and ne and will do a whereNull and whereNotNull, respectively
• contains is case insensitive

Usage

Take the following GraphQL schema

type Vehicle {
  make: String
  model: String
}

input VehicleFilterInput {
  AND: [VehicleFilterInput]
  OR: [VehicleFilterInput]

  "fields on the vehicle table"
  make: FilterQuery_String
  model: FilterQuery_String

  "fields not directly on the vehicle table"
  numberOfUsers: FilterQuery_Int
  highwayMPG: FilterQuery_Int
  cityMPG: FilterQuery_Int
  userSurveyRating: FilterQuery_Float
}

input VehicleSortInput {
  numberOfUsers: SortDirection
  userSurveyRating: SortDirection
}

type Query {
  vehicles(filter: VehicleFilterInput, sort: VehicleSortInput): [Vehicle]
}

Using this input, a user could construct the following filter query:

query GetVehicles ($filter: VehicleFilterInput, $sort: VehicleSortInput) {
  vehicles (filter: $filter, sort: $sort) {
    make
    model
  }
}

with variables

{
  "filter": {
    "AND": [
      { "make": { "eq": "nissan" } },
      { "model": { "in": ["altima", "sentra"] } },
      { "numberOfUsers": { "AND": [{ "gt": 1000 }, { "lt": 1999 }] } },
      {
        "OR": [
          { "highwayMPG": { "gt": 30 } },
          { "cityMPG": { "gte": 20 } }
        ]
      },
      { "userSurveyRating": { "gte": 80.5 } }
    ]
  },
  "sort": {
    "userSurveyRating": "ASC"
  }
}

This will specify that the user wants all vehicles whose make is "nissan", with model "altima" or "sentry", who has between 1000-1999 users (exclusive), whose user survey ratings is greater than or equal to 80.5 and whose MPG satisifies either highway strictly greater than 30mpg or city greater than or equal to 20mpg, and sorted by userSurveyRating ascending.

Known Limitations

• Implicit eq and in are not currently supported because GraphQL does not support union input types yet