get_union_json.ts

import fetch from "node-fetch";
import fs from "fs";

fetch(`http://localhost:4000/api`, {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    variables: {},
    query: `
      {
        __schema {
          types {
            kind
            name
            possibleTypes {
              name
            }
          }
        }
      }
    `,
  }),
})
  .then((result) => result.json())
  .then((result) => {
    // here we're filtering out any type information unrelated to unions or interfaces
    const filteredData = result.data.__schema.types.filter(
      (type) => type.possibleTypes !== null
    );
    result.data.__schema.types = filteredData;
    fs.writeFile("./fragmentTypes.json", JSON.stringify(result.data), (err) => {
      if (err) {
        console.error("Error writing fragmentTypes file", err);
      } else {
        console.log("Fragment types successfully extracted!");
      }
    });
  });