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Runtime API

Nearly all of Grats' work is done at build time where it extracts a schema definition. However there are a few features of Grats that require additional runtime handling.

If you define a field whose GraphQL name is different than its method name, Grats needs to configure that field's resover to call the correct field. If you define a field whose GraphQL name is different than its method name, Grats needs to configure that field's resover to call the correct field.

To enable these featurs to work, you must use a Grats-specific function to stantiate your GraphQL exectutor:

buildSchemaFromSDL​

buildSchemaFromSDL is a wrapper around buildSchema from graphql-js. It takes a GraphQL SDL string and returns a GraphQLSchema that has can be used to execute queries.

Options​

buildSchemaFromSDL does not currently accept any options.

Example​

import * as express from "express";
import { buildSchemaFromSDL } from "grats";

const sdl = fs.readFileSync("./schema.graphql", "utf8");
const schema = buildSchemaFromSDL(sdl);

// ... use `GraphQLSchema` schema to execute queries

For a full example see Build Mode.

extractGratsSchemaAtRuntime​

For getting a quick start and prototyping, you can use extractGratsSchemaAtRuntime. This works by running Grats's static analysis at startup time. This will make your server slower to startup, but may offer a nicer iteration loop during developemnt. It's not intended for production use.

You can think of extractGratsSchemaAtRuntime as running the Grats CLI and immediately passing the results to buildSchemaFromSDL`.

Options​

extractGratsSchemaAtRuntime accepts the following options:

  • emitSchemaFile - (optional) A path where Grats should write your schema file

Example​

import * as express from "express";
import { extractGratsSchemaAtRuntime } from "grats";

/** @gqlType */
class Query {
  /** @gqlField */
  hello(): string {
    return "Hello world!";
  }
}

const schema = extractGratsSchemaAtRuntime({
  emitSchemaFile: "./path/to/write/schema.graphql",
});
// ... use `GraphQLSchema` schema to execute queries

For a full example see Quick Start.