bridge-client.js

// @ts-check

import assert from "node:assert";
import { ESModulesEvaluator, ModuleRunner } from "vite/module-runner";

/**
 * @param {import("./types").BridgeClientOptions} options
 */
export function createBridgeClient(options) {
  /**
   * @param {string} method
   * @param  {...any} args
   * @returns {Promise<any>}
   */
  async function rpc(method, ...args) {
    const response = await fetch(options.bridgeUrl + "/rpc", {
      method: "POST",
      body: JSON.stringify({ method, args, key: options.key }),
    });
    assert(response.ok);
    const result = response.json();
    return result;
  }

  const runner = new ModuleRunner(
    {
      root: options.root,
      sourcemapInterceptor: "prepareStackTrace",
      transport: {
        invoke: async (payload) => {
          const response = await fetch(options.bridgeUrl + "/rpc", {
            method: "POST",
            body: JSON.stringify({ payload, key: options.key }),
          });
          assert(response.ok);
          return response.json();
        },
      },
      hmr: false,
    },
    new ESModulesEvaluator(),
  );

  // TODO: move this out
  /**
   * @param {Request} request
   * @returns {Promise<Response>}
   */
  async function handler(request) {
    try {
      const headers = request.headers;
      // @ts-ignore
      const meta = JSON.parse(headers.get("x-vite-meta"));
      headers.delete("x-vite-meta");
      const mod = await runner.import(meta.entry);
      return mod.default(new Request(meta.url, { ...request, headers }));
    } catch (e) {
      console.error(e);
      const message =
        "[bridge client handler error]\n" +
        (e instanceof Error ? `${e.stack ?? e.message}` : "");
      return new Response(message, { status: 500 });
    }
  }

  return { runner, rpc, handler };
}