Benzene instance

Every Benzene package relies on the Benzene class, which contains all the logic in executing the GraphQL request. The class can be found in the @benzene/core package and is re-exported in @benzene/http and @benzene/ws (use either one interchangeably).

import { Benzene } from "@benzene/http";
// is the same as
import { Benzene } from "@benzene/ws";

Most of the GraphQL behavior can be configured upon instantiating Benzene, such as context creation or error handling. Those configurations will apply when we use that Benzene instance in @benzene/http and @benzene/ws. For example, both @benzene/http and @benzene/ws will call the same formatErrorFn on execution errors and contextFn to create the resolver context.

This allows us to write such logic only once and use it everywhere.

Configuration

A Benzene instance will be instantiated with an options object, containing the following field:

• schema: (required) A GraphQLSchema instance.
• validateFn: A function to validate queries. See Validation.
• formatErrorFn: A function to format errors. See Error Handling.
• contextFn: A function to build resolvers context per query. See Building Context.
• compileQuery: A custom query compilation function. See Runtime.

The GraphQL Schema

Benzene is not concerned of the method that is used to generate the GraphQLSchema instance. We can create it with libraries like graphql-tools, type-graphql, GraphQL Nexus, and others.

Benzene methods

A Benzene instance has methods similar to those in the official graphql-js library. That includes graphql(), execute(), and subscribe(). The argument is the same with the graphql-js methods. The only difference is that each does not take in schema since we already define it above.

These methods allow you to execute GraphQL wherever you want.

Learn more at Benzene methods.

TypeScript usage

The Benzene class allows two generics TContext and TExtra. TContext is the resovlers context and TExtra would be the extra argument used in downstream packages.

When a Benzene instance is used by makeHandler from @benzene/http or @benzene/ws, the generics will be inherited.

const GQL = new Benzene<{ user: User }, { token: string }>({
  schema,
  contextFn: async ({ extra }) => {
    const user = await getUserFromToken(extra.token);
    return { user };
  },
});
 
const graphqlHTTP = makeHandler(GQL);
 
function onRequest(request) {
  const result = await graphqlHTTP(request, {
    token: request.headers["Authorization"],
  });
}