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    Via Profit Services / Core


    Via Profit services / Core - GraphQL server based on Express framework

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    Dependencies (peer)


    Lightweight, flexible, standalone implementation of a GraphQL HTTP (express middleware) which allows you to run an Express GraphQL server, build connections with pagination (Cursored or Limit-offset type), make your own extentions, read detailed logs, use global context with structured dataloaders and module containers, use some extra GraphQL Scalar types as DateTime, Money and so on

    List of our extentions:

    • accounts This package allows you to store and operate with user accounts and make user authorization. Very useful
    • permissions Standalone and lightweight implementation of graphql-shield. Beacuse we found it slow.
    • knex Adds some useful properties into global context like DB connection instance
    • geography Helps you to deal with cities, states and countries. All data included
    • subscriptions This package manage GrahpQL subscriptions
    • file-storage This package helps you to manage files, perporm image transformation, cropping
    • vehicles This package allows you to store and operate with vehicles data like model and brands. All data included
    • phones This package allows you to store and operate with phone numbers
    • redis Adds some useful properties into global context like Redis connection instance

    You can discover a full list of extentions in our organisation repository via-profit-services

    We always use those package in our commercial projects like CRM systems, websites and so on. Any help with development, testing and docs would be highly appreciated. Our contacts:

    LLC Via-Profit


    First of all you should install some peer dependencies by running:

    $ yarn add \
    express \
    graphql \
    moment \
    moment-timezone \

    And that's it. Let's write some code.

    Getting Started

    To build your first project you should do some things:

    • Make your GraphQL schema
    • Create an http server
    • Apply middleware

    Let's make it

    Note: You can see this example as Javascript in examples/simple

    import express from 'express';
    import http from 'http';
    import { factory } from '@via-profit-services/core';
    import schema from './schema';
    (async () => {
      const port = 9005;
      const app = express();
      const server = http.createServer(app);
      const { graphQLExpress } = await factory({
      app.use('/graphql', graphQLExpress);
      server.listen(port, () => {
        console.info(`GraphQL server started at http://localhost:${port}/graphql`);

    We strongly recommend using @graphql-tools package to build your schemas. This package helps to combine SDL and resolvers into a single executable schema. See makeExecutableSchema of @graphql-tools/schema module. For more details: example with graphql-tools

    Core module also exports its own typeDefs and resolvers. Those definitions would declare Query and Mutation root types.

    import express from 'express';
    import http from 'http';
    import { factory, typeDefs, resolver } from '@via-profit-services/core';
    import { makeExecutableSchema } from '@graphql-tools/schema';
    import customTypeDefs from 'schema.graphql';
    import customResolvers from './resolvers';
    (async () => {
      const port = 9005;
      const app = express();
      const server = http.createServer(app);
      // make schema by graphql-tools
      const schema = makeExecutableSchema({
        typeDefs: [
          customTypeDefs,// <-- Put your custom SDL here
          typeDefs, // <-- Put here the base core type definitions
        resolvers: [
          customResolvers, // < -- Put your custom resolvers here
          resolvers,  // <-- put here the base core resolvers
      const { graphQLExpress } = await factory({
      app.use('/graphql', graphQLExpress);
      server.listen(port, () => {
        console.info(`GraphQL server started at http://localhost:${port}/graphql`);


    • server (required). http.Server. Instance of http.Server
    • schema (required) GraphQLSchema. GraphQL schema
    • timezone. string. Server timezone. Default: UTC
    • logDir. string Path to directory of logs. Default: ./log
    • debug. boolean Displayed error stack and extensions in graphql response. Default: false for production and true for development mode
    • rootValue. any GraphQL parameter of execute method.
    • middleware Middleware | Middleware[] - Middleware or array of middlewares. See Middleware
    • persistedQueriesMap Record. Persisted Queries map (Object contains key: value pairs). See Relay Persisted Queries. If persisted queries map is passed, the server will ignore the query directive in body request and read the map using the documentId key, unless otherwise specified (see persistedQueryKey option).
    • persistedQueryKey string. Used only together with the persistedQueriesMap option. The name of the parameter that will be passed the ID of the query in the Persisted Queries map. Default: documentId


    The Core also adds scalar types:

    • Money - The value is stored in the smallest monetary unit (kopecks, cents, etc.). Real type - Int. E.g. For 250 USD this record returns value as 250000 (250$ * 100¢)
    • DateTime - Use JavaScript Date object for date/time fields.
    • Date - Use JavaScript Date object for date fields.
    • Time - And Time type.
    • URL - A field which value conforms to the standard URL format as specified in RFC3986.
    • EmailAddress - A field which value conforms to the standard internet email address format as specified in RFC822.
    • JSON - The JSON scalar type represents JSON values as specified by ECMA-404.
    • JSONObject - The JSONObject scalar type represents JSON objects as specified by ECMA-404.
    • Void - Represents NULL values

    Base TypeDefs

    The Core also adds GraphQL types:

    • interface Node - entity with required field: id. Used in Edges
    • type OrderDirection - Enum type to make the order (ASC, DESC)
    • type Error - entity fo display errors
    • type PageInfo - See Connection spec.
    • interface Edge - See Connection spec.
    • interface Connection - See Connection spec.
    • input BetweenDate - Between Date query type
    • input BetweenTime - Between Time query type
    • input BetweenDateTime - Between DateTime query type
    • input BetweenInt - Between Int query type
    • input BetweenMoney - Between Money query type


    To implement connections, according to the GraphQL Connection specification, you can use the types and functions included in the package:

    In schema (SDL):

    Note: GraphQL types OrderDirection, Connection, PageInfo, Edge and Node already declared in Core typedefs (see: Base TypeDefs)

    type Query {
        first: Int
        offset: Int
        after: String
        orderBy: [UserOrderBy!]
        between: UsersListBetween
        search: [UserFilterSearch!]
        filter: UserListFilter
      ): UserListConnection!
    Example of User type
    type User {
      id: ID!
      name: String!
      login: String!
      status: UserStatus!
      createdAt: DateTime!
      updatedAt: DateTime!
    Example of user status
    enum UserStatus {
    Ordering options
    input UserOrderBy {
      field: UserOrderField!
      direction: OrderDirection!
    Ordering fields of UserOrderBy input
    enum UserOrderField {
    Between filter
    input UsersListBetween {
      updatedAt: BetweenDateTime
      createdAt: BetweenDateTime
    User search filter
    input UserFilterSearch {
      field: UserFilterSearchField!
      query: String!
    Possible fields to search users
    enum UserFilterSearchField {
    Possible data to filter list of users
    input UserListFilter {
      id: [ID!]
      status: [UserStatus!]
    Users list bundle
    type UserListConnection implements Connection {
      totalCount: Int!
      pageInfo: PageInfo!
      edges: [UsersEdge!]!
    User edge bundle
    type UsersEdge implements Edge {
      node: User!
      cursor: String!

    In resolvers:

    import { GraphQLFieldResolver } from 'graphql';
    import { ServerError, buildCursorConnection, buildQueryFilter, CursorConnection, Context, InputFilter } from '@via-profit-services/core';
    type Resolvers = {
      Query: {
        list: GraphQLFieldResolver<unknown, Context, InputFilter>;
    const resolvers: Resolvers = {
      Query: {
        list: async (_parent, args, context) => {
          // convert input arguments to persist filter (See return value of this method)
          // Will be return `OutputFilter` type with normalized props
          // You can use this filter in your Model class
          const filter = buildQueryFilter(args);
          // Your model should return the data for the connection
          // You must provide totalCount and nodes yourself
          // limit, offset, and others can be returned
          // in the same form as received from the buildQueryFilter method
          // to simplify the selection from the database using filters, you
          // can use the package https://github.com/via-profit-services/knex
          const { totalCount, nodes, limit, offset, offset, where } = MyModelClass.getUsers(filter);
          // Now you can build the conection object like this:
          // method buildCursorConnection combine and return edges,
          // pageInfo and totalCount values
          const connection = buildCursorConnection({
          return connection;
    export default resolvers;


    You can use helpers by exporting them from the module:

    import { factory, resolvers, logFormatter, buildQueryFilter } from '@via-profit-services/core';


    Function returns object contains graphQLExpress - express middleware.

    Example of usage:

    import { factory } from '@via-profit-services/core';
    import express from 'express';
    import http from 'http';
    const server = http.createServer();
    const app = express();
    const { graphQLExpress } = factory({
    app.use('/graphql', graphQLExpress);


    Resolvers object contains:

    • Scalars resolvers
    • Root Query resolvers
      • core - Returns core version
    • Root Mutation resolvers
      • echo - Returns passed string


    SDL string with definitions of Scalars and Base TypeDefs


    OutputFilter containing the default values


    Convert input filter (partial from GraphQL request) into persist filter


    Format array of IDs into object with id key

    const ids = arrayOfIdsToArrayOfObjectIds(['1', '2', '3']);
    console.log(ids); // <-- [{id: '1'}, {id: '2'}, {id: '3'}]


    Collate rows for dataloader response From DataLoader docs: There are a few constraints this function must uphold:

    • The Array of values must be the same length as the Array of keys.
    • Each index in the Array of values must correspond to the same index in the Array of keys. For details here
    const dataloader = new DataLoader(async (ids: string[]) => {
      const nodes = await context.services.accounts.getUsersByIds(ids);
      return collateForDataloader(ids, nodes);


    Returns node IDs array

    const ids = extractNodeIds([
      {id: '1', name: 'Ivan'},
      {id: '2', name: 'Stepan'},
      {id: '3', name: 'Petruha'},
    console.log(ids); // <-- ['1', '2', '3'];


    Return array of fields of node

    const persons = [
      {id: '1', name: 'Ivan'},
      {id: '2', name: 'Stepan'},
      {id: '3', name: 'Petruha'},
    const names = extractNodeField(persons, 'name');
    console.log(names); // <-- ['Ivan', 'Stepan', 'Petruha']


    Wrap node to cursor object

    const filter = {
      offset: 0,
      limit: 15,
      where: [],
      orderBy: [{
        field: 'name',
        direction: 'desc',
    // Get persons list
    const persons = await service.getPersons(filter);
    // Map all persons to compile the edge for each
    const edges = persons.map((person) => {
      // You should passed node, cursor name and filter params
      return nodeToEdge(person, 'persons-cursor', filter);
    console.log(edges); // <-- [{ cursor: 'XGHJGds', node: { id: '1', name: 'Ivan' } }]


    Just encode base64 string Internal function. Used for GraphQL connection building

    const cursor = stringToCursor(JSON.stringify({ foo: 'bar' }));
    console.log(cursor); // <-- eyJmb28iOiJiYXIifQ==


    Just decode base64 string Internal function. Used for GraphQL connection building

    const data = cursorToString('eyJmb28iOiJiYXIifQ==');
    console.log(data); // <-- '{"foo":"bar"}'


    Returns cursor base64 cursor string by name and cursor payload

    const cursor = makeNodeCursor('persons-cursor', {
      offset: 0,
      limit: 15,
      where: [],
      orderBy: [{
        field: 'name',
        direction: 'desc',
    console.log(cursor); // <-- eyJvZmZzZXQiOjAsImxpbWl0IjoxNSwid2hlcmUiOltdLCJvcmRlckJ5IjpbeyJmaWVsZCI6Im5hbWUiLCJkaXJlY3Rpb24iOiJkZXNjIn1dfS0tLXBlcnNvbnMtY3Vyc29y


    Convert string to cursor base64 string and return payload

    const payload = getCursorPayload('eyJvZmZzZXQiOjAsImxpbWl0IjoxNSwid2hlcmUiOltdLCJvcmRlckJ5IjpbeyJmaWVsZCI6Im5hbWUiLCJkaXJlY3Rpb24iOiJkZXNjIn1dfS0tLXBlcnNvbnMtY3Vyc29y')
     * {
     *   offset: 0,
     *   limit: 15,
     *   where: [],
     *   orderBy: [ { field: 'name', direction: 'desc' } ]
     * }


    Returns Relay cursor bundle

    const cursorBundle = buildCursorConnection({
      totalCount: 3,
      offset: 0,
      limit: 2,
      nodes: [
        { id: '1', name: 'Ivan', createdAt: new Date(), updatedAt: new Date() },
        { id: '2', name: 'Stepan', createdAt: new Date(), updatedAt: new Date() },
    }, 'persons-cursor');
     * {
     *   totalCount: 3,
     *   edges: [
     *     {
     *       node: { id: '1', name: 'Ivan', ... },
     *       cursor:  'eyJvZmZzZXQiOjEsImxpbWl0Ijoy...'
     *     },
     *     {
     *       node: { id: '2', name: 'Stepan', ... },
     *       cursor:  'eyJvZmZzZXQiOjIsImxpbWl0Ij...'
     *     }
     *   ],
     *   pageInfo: {
     *     startCursor:  'eyJvZmZzZXQiOjEsImxpbWl0Ijoy...',
     *     endCursor:  'eyJvZmZzZXQiOjIsImxpbWl0Ij...',
     *     hasPreviousPage: false,
     *     hasNextPage: true
     *   }
     * }


    Creates an object which contains a specific key

    const source = {
      foo: 'Foo',
      bar: 12,
    const record = extractKeyAsObject(source, 'bar');
    console.log(record); // <-- { bar: 12 }


    Wrap types resolvers in schema. You can wrap types without resolvers - will be created noop-resolver to wrap the field.

    Note: The resolver function should return all the received parameters.

    const { graphQLExpress } = await factory({
      middleware: [
        ({ schema }) => ({
          schema: fieldsWrapper(schema, (params) => {
            const { resolver, source, args, context, info } = params;
            // Do something
            return params;


    Middleware is a special function that allows you to expand the GraphQL Context by adding new parameters into it, as well as performing GraphQL validation at the ValidationRule. In addition, you can modify the current GraphQL scheme.

    Middleware factory function will be called on every GraphQL request. Keep it in mind. When calling function, it would passed a set of parameters which contains a current context value, current schema, http request and so on. The function could return nothing or return the modified value of one of the parameters.

    Note: Middlewares order. Since each middleware mutates the context and returns it back. The presence of a property parameter in the context will depend on each of these middleware.

    Will be passed:

    • config - Parameters that were passed during core factory called.
    • context - The current context value returned from the previous middleware, or the default context value if no middleware has been executed before.
    • schema - The current GraphQL schema returned from the previous middleware, or the initial schema if no middleware has been executed before.
    • extensions - The current Extensions object returned from the previous middleware, or the initial extensions if no middleware has been executed before.
    • request - HTTP request (Express.Request)

    Possible return:

    • context - You should mutated this context value. Not override and not merge with spread operator.
    • schema - You should mutated this schema value. Not override and not merge with spread operator.
    • extensions - You should mutated this schema value. Not override and not merge with spread operator.
    • validationRule - You can return GraphQL validation rule or array of validation rules. All rules that will be returned from middlewares will be concatenated and passed to GraphQL execute method

    Note: Use wrapper function to make closure and cache.

    To create your simple middleware you can see this example:

    import { factory, Middleware } from '@via-profit-services/core';
    // function wrapper
    const customMiddlewareFactory = () => {
      // Middleware factory which should passed to middleware props
      const middleware: Middleware = ({ context }) => {
        // Inject custom propertied into context
        context.myCustomContextProp = context.myCustomContextProp { 
          foo: 'The Foo',
        // Do not forget return it
        return {
      return middleware;
    const { graphQLExpress } = await factory({
      middleware: [

    Warning! Do not use spread operator while combining old current context and new context value. See example below:

    Warning! This code is not valid

    // !!! This code is not valid
    const middleware: Middleware = ({ context }) => ({
      myCustomContextProp: {
        foo: 'bar',

    For TypeScript you can expand the types using the Declaration files *.d.ts. Now you can use TypeScript autocompletion in the IDE, which will contain the current Core types with your custom types.

    declare module '@via-profit-services/core' {
      // extend standard Context object
      interface Context {
        myCustomContextProp: {
          foo: string;
      // extend standard services collection
      interface ServicesCollection {
        myService: MyServiceClass;


    Default state of GraphQL Context:

    • timezone - Provied with initial properties (See API) .Default: UTC.
    • services - Provied with collection of any services that you make (See Middleware)
    • emitter - Provied with Event Emitter class (See EventEmitter)
    • request - Provied with Express server request (See Express API)
    • schema - Provied with GraphQL current schema

    You can extend default context value. See Middleware section for more details.

    Event Emitter

    Context contains the emitter property by default - Event Emitter this class are empty by deafult. You can extend it


    The MIT License.


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