Fastify

Use MeshQL with Fastify via createMeshFastifyPlugin.

Prerequisites

• Node.js 22+
• Fastify 4 or 5

Install

npm install meshql-core meshql-http fastify

Server

import Fastify from "fastify";
import { createMesh, buildSelectSql, type MeshSchema } from "@meshql/core";
import { createMeshFastifyPlugin } from "@meshql/http/fastify";

const schema: MeshSchema = {
  entities: {
    user: { type: {} as { id: number; name: string }, fields: ["id", "name"], table: "users" },
    token: {
      type: {} as { accessToken: string },
      fields: ["accessToken"],
      table: "tokens",
      columns: { accessToken: "access_token" },
    },
  },
  joins: {
    "user.tokens": {
      entity: "token",
      on: "tokens.user_id = users.id",
      type: "many",
    },
  },
};

const mesh = createMesh(schema);

mesh.resolve("user", async (plan) => {
  const { sql, params } = buildSelectSql(plan, schema);
  return [{ user_id: 1, user_name: "Ada", tokens_accessToken: "tok_abc" }];
});

const fastify = Fastify();

await fastify.register(createMeshFastifyPlugin(mesh, { basePath: "/mesh" }));

await fastify.listen({ port: 3001, host: "0.0.0.0" });
console.log("MeshQL on http://localhost:3001/mesh");

Options

interface MeshFastifyOptions {
  basePath?: string; // default: "/mesh"
}

Client test

import { createClient } from "@meshql/client";

const client = createClient({ url: "http://localhost:3001/mesh" });
const user = await client.query(
  { user: { id: true, name: true, tokens: { accessToken: true } } },
  { entityId: "1" },
);

Reference

HTTP adapters