Get SDL from GraphQL introspection query

graphql-sdl-from-introspection.ts

import {
  buildClientSchema,
  buildSchema,
  getIntrospectionQuery,
  GraphQLSchema,
  printSchema,
} from "graphql";
import fetch from "node-fetch";

const GRAPHQL_API_URL = "";
const GRAPHQL_API_AUTH_TOKEN = "";

(async () => {
  const resp = await fetch(GRAPHQL_API_URL, {
    method: "POST",
    headers: {
      Authorization: `Basic ${GRAPHQL_API_AUTH_TOKEN}`,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({ query: getIntrospectionQuery() }),
  });

  const { data } = await resp.json();

  // Convert to SDL
  console.log(printSchema(buildClientSchema(data)));

  // Get GraphQLSchema type
  console.log(buildSchema(data));
})();