ts-pnp-paths.js

#!/usr/bin/env node
const path = require("path");
const fs = require("fs");
const { promisify } = require("util");
const { createHash } = require("crypto");
const automatedConfigMarker =
  "//This file is auto-generated by ts-pnp-path and should not be edited directly." +
  require("os").EOL;

//Read args in a no-dependencies-needed way. = or space between arg values.
const argsObject = process.argv
  .join(" ")
  .split("-")
  .reduce((acc, arg) => {
    const [argKey, argValue] = arg.split(/[ =]/);
    acc[argKey.replace(/^-?/, "").toLowerCase()] = argValue || true;
    return acc;
  }, {});
const {
  configPath = argsObject.c || "./tsconfig.pnp.json",
  depth = argsObject.d,
  info = argsObject.i || false,
  force = argsObject.f || false,
  silent = argsObject.s || false,
  rootDir = argsObject.r || process.cwd()
} = argsObject;

function log(...params) {
  !silent && console.log(...params);
}

function logInfo(...params) {
  info && log(...params);
}

//main async processing
(async () => {
  //Start load of existing config.
  const existingConfigLoad = promisify(fs.readFile)(
    path.resolve(rootDir, configPath),
    "utf8"
  )
    .then(fileContents =>
      fileContents.startsWith(automatedConfigMarker)
        ? JSON.parse(fileContents.substring(automatedConfigMarker.length))
        : Promise.reject(
            new Error(
              `The file on path "${path.resolve(
                rootDir,
                configPath
              )}" seems to not be generated by ts-pnp-paths.
Use another --configPath or remove this file manually to continue."`
            )
          )
    )
    .catch(err => (err.code === "ENOENT" ? null : Promise.reject(err)));

  //Check for .pnp.js under root. Quit out and clean up if it's not there.
  const pnpPath = path.resolve(rootDir, ".pnp.js");
  if (!fs.existsSync(pnpPath)) {
    logInfo(
      `No .pnp.js exists under "${rootDir}", cleaning up "${configPath}."`
    );
    await existingConfigLoad
      .then(
        file =>
          file !== null &&
          promisify(fs.unlink)(path.resolve(rootDir, configPath))
      )
      .catch(err => log(`Could not remove "${configPath}"`, err));
    return;
  }

  //Hash .yarn.lock and compare with potential previous generated .tsconfig. Quit out if yarn.lock is the same.
  const [existingConfig, yarnLockChecksum] = await Promise.all([
    existingConfigLoad,
    promisify(fs.readFile)(path.resolve(rootDir, "./yarn.lock"), "utf8").then(
      fileContents =>
        //actually not async but keeps down the var bloat
        createHash("sha1")
          .update(fileContents, "utf8")
          .digest("hex")
    )
  ]);
  if (
    !force &&
    existingConfig != null &&
    existingConfig.generatedForDependencyDepth === depth &&
    existingConfig.generatedForYarnLockChecksum === yarnLockChecksum
  ) {
    logInfo(
      `Previous checksum for yarn.lock matches current, will not regenerate "${configPath}". Use --force to bypass.`
    );
    return;
  }

  //list dependency tree by calling yarn cli with supplied depth argument
  //this will result in a potentially really big string and JSON, could be changed to buffer
  const deps = await new Promise((resolve, reject) => {
    let outResult = "";
    let errResult = "";
    const yarnList = require("child_process").spawn("yarn", [
      "list",
      "--json",
      ...(depth != null ? [`--depth=${depth}`] : [])
    ]);
    yarnList.stdout.on("data", data => {
      outResult += data.toString();
    });
    yarnList.stderr.on("data", data => {
      errResult += data.toString();
    });
    yarnList.on("close", code =>
      code === 0 ? resolve(JSON.parse(outResult)) : reject(errResult)
    );
  });

  //Pnp file is needed for package location
  const pnp = require(pnpPath);

  //Traverse dependency tree and use .pnp.js to find package location.
  //TODO maybe: Breadth-first traversal would skip out early on more iterations, but perf implications are dwarfed by yarn cli call.
  const pathMap = (function reduceDepTreeToMap(
    nodes,
    targetMap = new Map(),
    depth = 0
  ) {
    return nodes == null
      ? targetMap
      : nodes.reduce((acc, { name, children }) => {
          const indexOfVerSeparator = name.lastIndexOf("@");
          const depName = name.substring(0, indexOfVerSeparator);
          const depVersion = name.substring(indexOfVerSeparator + 1);
          //Get previous path if accumulated.
          const [prevDepth, prevVersion] = acc.get(depName) || [];
          if (
            //package has been located previously and
            prevDepth != null &&
            //package has been located at a shallower dependency depth ...
            (prevDepth < depth ||
              //or, package has been located on the same dependency depth with >= version...
              (prevDepth === depth && prevVersion >= depVersion))
          ) {
            //...,then use that one instead.
            return acc;
          }
          //Get package information from pnp
          const packageInformation = pnp.getPackageInformation({
            name: depName,
            reference: depVersion
          });
          if (packageInformation == null) {
            logInfo(
              `Could not get package information of ${name}, will not add path for package.`
            );
            return acc;
          }
          acc.set(depName, [
            depth,
            depVersion,
            packageInformation.packageLocation
          ]);
          return reduceDepTreeToMap(children, targetMap, depth + 1);
        }, targetMap);
  })(deps.data.trees);

  //Generate finalized paths for tsconfig where @types/ packages are merged to package name.
  const paths = Array.from(pathMap.entries()).reduce(
    (acc, [packageName, [_depth, _version, path]]) => {
      //If this is a types package, stripping the "@types/" prefix is needed
      const pathKey =
        packageName.indexOf("@types/") == 0
          ? packageName.substring(7)
          : packageName;
      const prevPackagePaths = acc[pathKey];
      //combine @types/[PACKAGENAME] with [PACKAGENAME]
      acc[pathKey] =
        prevPackagePaths != null ? [...prevPackagePaths, path] : [path];
      return acc;
    },
    {}
  );

  //Finalize new tsconfig content
  const tsConfigPnp = JSON.stringify(
    {
      //Save info about this execution for next time
      generatedForYarnLockChecksum: yarnLockChecksum,
      generatedForDependencyDepth: depth,
      compilerOptions: {
        //Base url needs to be set to something for paths to work.
        baseUrl: "",
        paths
      }
    },
    null,
    2
  );

  //Write file
  await promisify(fs.writeFile)(
    path.resolve(rootDir, configPath),
    automatedConfigMarker + tsConfigPnp
  );
  log(`Generated "${configPath}" with pnp path mappings for Typescript`);
})().catch(err => console.error(`Could not generate "${configPath}"`, err));