Deno esbuild plugin

esbuild_plugin.ts

import {
  Loader,
  PluginBuild,
} from "https://deno.land/x/esbuild@v0.15.15/mod.js";
import { dirname, join } from "https://deno.land/std@0.114.0/path/mod.ts";
import { createLogger } from "packages/logs/mod.ts";

const log = createLogger("esbuildDenoPlugin", "debug");
const logError = createLogger("esbuildDenoPlugin", "error");

const LOCAL_NAMESPACE = "deno-local";
const REMOTE_NAMESPACE = "deno-remote";
const NPM_NAMESPACE = "npm";
const NPM_RELATIVE_DEPENDENCY = "npm_relative_dependency";
const NPM_SCOPED_NAMESPACE = "npm_scoped";
const NPM_PACKAGE_JSON_NAMESPACE = "npm_package_json";
const REMOTE_MODULE_REGEX = /^https?:\/\//;

const cacheLocations = await getCacheLocations();

async function getCacheLocations() {
  log("Fetching cache locations...");
  const p = Deno.run({
    cmd: [
      "deno",
      "info",
    ],
    stdout: "piped",
  });
  const { code } = await p.status();
  if (code !== 0) {
    throw new Error("deno info failed");
  }
  const decoder = new TextDecoder("utf-8");
  const output = decoder.decode(await p.output());
  // deno-lint-ignore no-control-regex
  const plainText = output.replace(/\x1b\[[0-9;]*m/g, "");
  const lines = plainText.split("\n");
  const denoDirLocation = lines.find((line) =>
    line.startsWith("DENO_DIR location: ")
  )?.split(
    "DENO_DIR location: ",
  )[1];
  const remoteModulesCache = lines.find((line) =>
    line.startsWith("Remote modules cache: ")
  )?.split(
    "Remote modules cache: ",
  )[1];
  const npmModulesCacheRoot =
    lines.find((line) => line.startsWith("npm modules cache: "))?.split(
      "npm modules cache: ",
    )[1] ?? "./.deno/npm";
  const npmModulesCache = join(npmModulesCacheRoot, "registry.npmjs.org");
  log("Cache locations fetched successfully.");
  return {
    denoDirLocation,
    remoteModulesCache,
    npmModulesCache,
  };
}

async function checkIfNpmModule(pathWithNamespace: string) {
  try {
    const packageJsonString = await Deno.readTextFile(
      join(Deno.env.get("BFF_ROOT") ?? Deno.cwd(), "package.json"),
    );
    const packageJson = JSON.parse(packageJsonString);
    const dependencies = Object.keys(packageJson.dependencies ?? {});
    const path = pathWithNamespace.split("/")[0];
    const isPackageJson = dependencies.includes(path);
    return isPackageJson;
  } catch (error) {
    if (error instanceof Deno.errors.NotFound) {
      return false;
    }
    throw error;
  }
}

export const esbuildDenoPlugin = {
  name: "deno",
  setup(build: PluginBuild) {
    const { onResolve, onLoad } = build;

    onResolve({ filter: REMOTE_MODULE_REGEX }, (args) => {
      log(`Resolving remote module: ${args.path}`);
      return { path: args.path, namespace: REMOTE_NAMESPACE };
    });

    onResolve({ filter: /.*/, namespace: REMOTE_NAMESPACE }, (args) => {
      const path = new URL(args.path, args.importer).href;
      if (path.startsWith("node:")) {
        return { path, namespace: "empty" };
      }
      log(`Resolving remote module: ${args.path}`);
      const namespace = REMOTE_NAMESPACE;
      return { path, namespace };
    });

    onResolve({ filter: /.*/, namespace: NPM_NAMESPACE }, async (args) => {
      const [importerPackageName, ...rest] = args.importer.split("/");
      let path = args.path;
      if (path.endsWith(".js")) {
        path = path.replace(".js", "");
      }
      const isRelativeNpmPath = path.startsWith(".") || path.startsWith("/");
      if (isRelativeNpmPath) {
        const everythingExceptLast = rest.slice(0, -1);
        path = everythingExceptLast.join("/") + "/" + path + ".js";
        log("resolving relative npm module:", path);
        const mainEntrypointPath = await loadCachedNpmModulePath(
          importerPackageName,
        );
        path = path = join(dirname(mainEntrypointPath), path);
        return { path, namespace: NPM_RELATIVE_DEPENDENCY };
      }
      log("resolving npm namespaced module:", path);
      return { path, namespace: NPM_PACKAGE_JSON_NAMESPACE };
    });

    onResolve({ filter: /.*/, namespace: NPM_RELATIVE_DEPENDENCY }, (args) => {
      const pathWithExtension = args.path.endsWith(".js")
        ? args.path
        : args.path + ".js";
      if (args.path.startsWith(".")) {
        log(`Resolving npm filepath dependency: ${args.path}`);
        const path = join(dirname(args.importer), `${pathWithExtension}`);
        return { path, namespace: NPM_RELATIVE_DEPENDENCY };
      }

      // Check if the module is scoped
      const isScoped = args.path.startsWith("@") && args.path.includes("/");

      log(`Resolving npm bare specifier dependency: ${args.path}`);
      return {
        path: args.path,
        namespace: isScoped ? NPM_SCOPED_NAMESPACE : NPM_NAMESPACE,
      };
    });

    onResolve({ filter: /.*/, namespace: NPM_SCOPED_NAMESPACE }, async (
      args,
    ) => {
      const [namespace, packageName, ...rest] = args.importer.split("/");
      const packageIdentifier = `${namespace}/${packageName}`;
      let paths = args.path;
      if (paths.startsWith(".")) {
        paths = paths.replace(".", "");
      }
      const mainEntrypointPath = await loadCachedNpmModulePath(
        packageIdentifier,
      );
      const restExceptLast = rest.slice(0, -1);
      const path = join(
        dirname(mainEntrypointPath),
        restExceptLast.join("/"),
        paths,
      );

      log(`Resolving npm scoped namespace dependency: ${args.path}`);
      return { path, namespace: NPM_RELATIVE_DEPENDENCY };
    });

    onResolve({ filter: /.*/, namespace: NPM_PACKAGE_JSON_NAMESPACE }, async (
      args,
    ) => {
      if (args.path.startsWith(".")) {
        const mainEntrypointPath = await loadCachedNpmModulePath(
          args.importer,
        );
        const path = join(dirname(mainEntrypointPath), args.path);
        log(`Resolving npm package_json dependency: ${args.path}`);
        return { path, namespace: NPM_RELATIVE_DEPENDENCY };
      }
      log(`Resolving npm package.json: ${args.path}`);
      return { path: args.path, namespace: NPM_PACKAGE_JSON_NAMESPACE };
    });

    onResolve({ filter: /.*/ }, async (args) => {
      if (args.kind === "entry-point") {
        return;
      }

      const isNpmModule = await checkIfNpmModule(args.path);

      if (isNpmModule) {
        log(`Resolving npm module: ${args.path}`);
        if (args.path.includes("posthog-node")) {
          return { path: args.path, namespace: "empty" };
        }
        return { path: args.path, namespace: NPM_PACKAGE_JSON_NAMESPACE };
      }

      if (args.path.startsWith("npm:") || isNpmModule) {
        const path: string = args.path.split("npm:")[1] ?? args.path;
        log(`Resolving npm prefixed module: ${args.path}`);
        return { path, namespace: NPM_NAMESPACE };
      }

      if (args.path.endsWith(".graphql")) {
        const path =
          new URL(import.meta.resolve(`packages/__generated__/${args.path}.ts`))
            .pathname;
        return {
          path,
          namespace: LOCAL_NAMESPACE,
        };
      }

      const resolvedPath = import.meta.resolve(args.path);
      if (resolvedPath.startsWith("file://")) {
        const path = resolvedPath.replace("file://", "");
        log(`Resolving local module: ${args.path}`);
        return {
          path,
          namespace: LOCAL_NAMESPACE,
        };
      }
      if (resolvedPath.startsWith("http")) {
        const path = new URL(resolvedPath).href;
        log(`Resolving remote module: ${args.path}`);
        return {
          path,
          namespace: REMOTE_NAMESPACE,
        };
      }
      if (resolvedPath.startsWith("npm:")) {
        const path: string = args.path.split("npm:")[1] ?? args.path;
        return { path, namespace: NPM_NAMESPACE };
      }
    });

    function getLoader(extension: string): Loader {
      const validExtensions = [".js", ".jsx", ".ts", ".tsx"];
      if (validExtensions.includes(extension)) {
        return extension as Loader;
      }
      return "ts";
    }

    onLoad({ filter: /.*/, namespace: "empty" }, (args) => {
      // Creating a Proxy to handle any named import dynamically.
      // This will cater to both default and named exports.
      const contents = `
        const handler = {
          get: (target, prop) => undefined
        };
        const moduleProxy = new Proxy({}, handler);
        export default moduleProxy;
        export const Buffer = undefined;
      `;
      const loader = "js"; // JavaScript loader for the content

      log(`Handling 'empty' namespace for module: ${args.path}`);
      return { contents, loader };
    });

    onLoad({ filter: /.*/, namespace: REMOTE_NAMESPACE }, async (args) => {
      const cachePath = cacheLocations.remoteModulesCache + "/" + args.path;
      let contents;

      try {
        await Deno.stat(cachePath);
        contents = await Deno.readTextFile(cachePath);
      } catch (error) {
        if (error instanceof Deno.errors.NotFound) {
          const source = await fetch(args.path);
          if (!source.ok) {
            throw new Error(
              `Failed to fetch ${args.path}: ${source.status} ${source.statusText}`,
            );
          }
          contents = await source.text();
        } else {
          throw error;
        }
      }

      const pattern = /\/\/# sourceMappingURL=(\S+)/;
      const match = contents.match(pattern);
      if (match) {
        const sourceMapUrl = new URL(match[1], args.path);
        const dataurl = await fetchSourceMap(sourceMapUrl);
        const comment = `//# sourceMappingURL=${dataurl}`;
        contents = contents.replace(pattern, comment);
      }
      const { pathname } = new URL(args.path);
      const ext = pathname.match(/[^.]+$/);
      const loader = getLoader(ext ? ext[0] : "");

      return { contents, loader };
    });

    onLoad({ filter: /.*/, namespace: LOCAL_NAMESPACE }, async (args) => {
      const source = await Deno.readTextFile(args.path);
      const graphqlTags = extractGraphqlTags(source);
      let contents = source;
      if (graphqlTags.length > 0) {
        contents = await replaceTagsWithImports(source, graphqlTags);
      }
      const ext = args.path.match(/[^.]+$/);
      const loader = (ext ? ext[0] : "ts") as Loader;

      log(`Loading local module: ${args.path}`);
      return { contents, loader };
    });

    onLoad({ filter: /.*/, namespace: NPM_NAMESPACE }, async (args) => {
      // Get the npm identifier from the path
      const npmIdentifier = args.path.split("/")[0];
      const pathParts = args.path.split("/").slice(1);

      const mainEntrypointPath = await loadCachedNpmModulePath(npmIdentifier);

      let requestedFile;
      if (pathParts.length === 0) {
        requestedFile = mainEntrypointPath;
      } else {
        const mainModuleDir = dirname(mainEntrypointPath);
        const requestedFileWithoutExtension = join(mainModuleDir, ...pathParts);
        requestedFile = `${requestedFileWithoutExtension}.js`;
      }

      const ext = requestedFile.split(".").pop();
      const loader = getLoader(ext ?? "");

      // Read the contents of the requested file
      log("trying to load", requestedFile);
      let contents;
      try {
        contents = await Deno.readTextFile(requestedFile);
      } catch (e) {
        logError(`Could not find module ${npmIdentifier} at ${requestedFile}`);
        contents = "";
      }

      log(`Loading npm module: ${args.path}`);
      return { contents, loader };
    });

    onLoad(
      { filter: /.*/, namespace: NPM_RELATIVE_DEPENDENCY },
      async (args) => {
        const ext = args.path.match(/[^.]+$/);
        const loader = (ext ? ext[0] : "ts") as Loader;

        log(`Loading npm relative dependency: ${args.path}`);
        // Read the contents of the requested file
        const contents = await Deno.readTextFile(args.path);
        return { contents, loader };
      },
    );

    onLoad({ filter: /.*/, namespace: NPM_SCOPED_NAMESPACE }, async (args) => {
      log(`Loading npm scoped namespace: ${args.path}`);
      // Get the scoped npm identifier from the path
      const [scope, packageName] = args.path.split("/").slice(0, 2);
      const scopedNpmIdentifier = `${scope}/${packageName}`;
      const pathParts = args.path.split("/").slice(2);

      const mainModuleDir = await loadCachedNpmModulePath(
        scopedNpmIdentifier,
      );

      const requestedFileWithoutExtension = join(
        dirname(mainModuleDir),
        ...pathParts,
      );
      const requestedFile = `${requestedFileWithoutExtension}.js`;

      const ext = requestedFile.split(".").pop();
      const loader = getLoader(ext ?? "");

      // Read the contents of the requested file
      const contents = await Deno.readTextFile(requestedFile);

      return { contents, loader };
    });

    onLoad(
      { filter: /.*/, namespace: NPM_PACKAGE_JSON_NAMESPACE },
      async (args) => {
        const [npmIdentifier, child] = args.path.split("/");
        const mainEntrypointPath = await loadCachedNpmModulePath(npmIdentifier);
        let contents = await Deno.readTextFile(mainEntrypointPath);
        if (child) {
          const entrypointPath = join(dirname(mainEntrypointPath), child);
          contents = await Deno.readTextFile(`${entrypointPath}.js`);
        }
        log(`Loading npm package.json: ${args.path}`);
        return { contents, loader: "js" };
      },
    );
  },
};

async function fetchSourceMap(url: URL) {
  const map = await fetch(url);
  const type = map.headers.get("content-type") ?? undefined;
  const buffer = await map.arrayBuffer();
  const blob = new Blob([buffer], { type });
  const reader = new FileReader();
  return new Promise((cb) => {
    reader.onload = (e) => cb(e.target?.result);
    reader.readAsDataURL(blob);
  });
}

async function loadCachedNpmModulePath(
  npmIdentifier: string,
  retry = true,
): Promise<string> {
  const cachePath = `${cacheLocations.npmModulesCache}/${npmIdentifier}`;
  const registryPath = `${cachePath}/registry.json`;
  let registryJsonString;
  try {
    registryJsonString = await Deno.readTextFile(registryPath);
  } catch (error) {
    if (error instanceof Deno.errors.NotFound) {
      if (npmIdentifier.includes("/") && retry) {
        const [packageName] = npmIdentifier.split("/");
        return loadCachedNpmModulePath(packageName, false);
      }

      if (npmIdentifier.startsWith("npm:") && retry) {
        return loadCachedNpmModulePath(npmIdentifier.split(":")[1], false);
      }
      logError(
        `Could not find module ${npmIdentifier} in cache at ${cachePath}`,
      );
    }
  }

  if (registryJsonString == null) {
    return `infra/utils/empty.ts`;
  }

  const registryJson = JSON.parse(registryJsonString);
  const currentVersion = registryJson["dist-tags"].latest;
  const currentVersionPath = `${cachePath}/${currentVersion}`;
  try {
    const packageJsonString = await Deno.readTextFile(
      `${currentVersionPath}/package.json`,
    );
    const packageJson = JSON.parse(packageJsonString);
    const mainFile = packageJson.main;
    const mainFilePath = `${currentVersionPath}/${mainFile}`;
    return mainFilePath;
  } catch (error) {
    if (error instanceof Deno.errors.NotFound) {
      logError(
        `Could not find module ${npmIdentifier} in cache at ${currentVersionPath}`,
      );
      return `infra/utils/empty.ts`;
    }
    throw error;
  }
}

const extractGraphqlTags = (contents: string) => {
  const matches = Array.from(contents.matchAll(/graphql`([\s\S]+?)`/g)).map(
    (match) => match[1].trim(),
  );
  return matches;
};

const replaceTagsWithImports = async (
  contents: string,
  matches: string[],
) => {
  let updatedContents = contents;
  const artifactsDirectory = "packages/__generated__";

  const replacements: Record<string, string> = {};

  for (const match of matches) {
    const pattern = /^(?<operationType>\w+)\s+(?<operationName>\w+)/m;

    const { _operationType, operationName } = match.match(pattern)?.groups ??
      {};
    const generatedFileName = `${operationName}.graphql.ts`;
    const generatedFilePath = join(artifactsDirectory, generatedFileName);

    try {
      const filesystemPath =
        new URL(import.meta.resolve(generatedFilePath)).pathname;
      await Deno.stat(filesystemPath);
      const replacement =
        `(async () => { const importedModule = await import('${generatedFilePath}'); return importedModule.default; })()`;

      replacements[match] = replacement;
    } catch (_error) {
      logError(
        `Generated Relay file not found for query: ${generatedFilePath}, skipping replacement.`,
      );
    }
  }

  updatedContents = updatedContents.replace(
    /graphql`([\s\S]+?)`/g,
    (fullMatch, group) => {
      const trimmedGroup = group.trim();
      return replacements[trimmedGroup] || fullMatch;
    },
  );

  return updatedContents;
};