GraphQL Scalars 1.0 is out!

Arda TanrikuluThursday, Aug 8th 2019

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The GraphQL Specification has theInt, Float, String, Booleanand ID Scalar types by default. Those scalar types help you identify the data and validate it before transferring it between client and server. But you might need more specific scalars for your GraphQL application, to help you better describe and validate your app's data.

Validation Using Scalars

For example, you have a String field, but you need to validate upcoming or ongoing string data using regular expressions. So you should have this validation on each end; one in the client, the other one in the server and maybe there is another on a source. Instead of duplicating the same logic in different parts of the project, you can use EmailAddress scalar type that does the validation inside GraphQL for you.

Serialization and Parsing

The other benefit of using GraphQL scalar types is parsing and serializing while transferring data. For example, you have DateTime data, but it is transferred as String due to restrictions of JSON, and each time you receive and pass the data, you have to parse the string and create a JavaScript Date instance while also serializing it to string before passing it to the client. Instead of having that logic in your implementation, you can just use DateTime scalar and you would work with native JavaScriptDate instances directly like it is one of primitive types such as string, number and boolean.

What's New?

We've recently taken over the maintenance of GraphQL-Scalars (opens in a new tab) library from the amazing team of OK-Grow!

Since then, we completely rewrote the library using TypeScript, upgraded all dependencies, closed all the issues and PRs and increased the number of scalars in the package with new scalars like: BigInt(Long) , GUID , HexColorCode , Hexadecimal , IPv4 , IPv6 , ISBN , MAC , JSON and more. You can see all scalars in the README (opens in a new tab).

Mocking

Apollo Server provides mocks built-in scalars such as Int , String , Float , ID and Boolean . What if you need same thing for our scalars? So, we provide you mocking functions for each scalar in this package. You can add those easily in your server for mocking the schema.

import { ApolloServer } from 'apollo-server'
import { makeExecutableSchema } from 'graphql-tools'
// import all scalars and resolvers
import { typeDefs, resolvers, mocks } from 'graphql-scalars'
// Alternatively, import individual scalars and resolvers
// import { DateTimeResolver, DateTimeTypeDefinition, DateTimeMock, ... } from "graphql-scalars"
 
const server = new ApolloServer({
  typeDefs: [
    // use spread syntax to add scalar definitions to your schema
    ...typeDefs
    // DateTimeDefinition,
    // ...
    // ... other type definitions ...
  ],
  resolvers: {
    // use spread syntax to add scalar resolvers to your resolver map
    ...resolvers
    // DateTimeResolver,
    // ...
    // ... remainder of resolver map ...
  },
  mocks: {
    // use spread syntax to add scalar resolvers to your resolver map
    ...mocks
    // DateTimeMock,
    // ...
    // ... other mocks ...
  }
})