medusa-starter/build.mjs

import swc from "@swc/core";
import fs from "node:fs/promises";
import path from "path";

const inputDir = "./src";
const outputDir = "./dist";
const compileExtensions = [".ts", ".tsx", ".js", ".jsx"];
const ignoreExtensions = [".md"];
const dryRun = false;

const started = Date.now();

const inputDirName = path.basename(inputDir);
const outputDirName = path.basename(outputDir);

// Recursively find all files to compile
const findFiles = async (dir, { allowNonExistent } = {}) => {
  try {
    let files = await fs.readdir(dir, { withFileTypes: true });
    let paths = await Promise.all(
      files.map(async (file) => {
        const res = path.join(dir, file.name);
        return file.isDirectory() ? findFiles(res) : res;
      }),
    );
    return paths.flat();
  } catch (e) {
    if (allowNonExistent && e.code === "ENOENT") {
      return [];
    }
    throw e;
  }
};

const files = await findFiles(inputDir);

// Clear out dir
await fs.rm(outputDir, { recursive: true }).catch(() => {});

const getOutputPath = (file, config) => {
  const { inputDir, outputDir, targetExtension } = config;

  const relativePath = file.replace(inputDirName, outputDirName);
  let outputPath = relativePath;

  if (targetExtension) {
    const currentExtension = path.extname(outputPath);
    outputPath = outputPath.replace(currentExtension, targetExtension);
  }

  return outputPath;
};

const writeToOut = async (file, content, config) => {
  const outputPath = getOutputPath(file, config);
  if (dryRun) {
    console.log(`Writing ${file} to ${outputPath}`);
    return;
  }
  await fs.mkdir(outputPath.replace(/\/[^/]+$/, ""), { recursive: true });
  await fs.writeFile(outputPath, content);
};

const copyToOut = async (file, config) => {
  const outputPath = getOutputPath(file, config);

  if (dryRun) {
    console.log(`Copying ${file} to ${outputPath}`);
    return;
  }
  let dirNameRegex = new RegExp("\\" + path.sep + "([^\\" + path.sep + "]+)$");
  await fs.mkdir(outputPath.replace(dirNameRegex, ""), { recursive: true });
  await fs.copyFile(file, outputPath);
};

const medusaTransform = async (file) => {
  if (compileExtensions.some((ext) => file.endsWith(ext))) {
    const outputPath = getOutputPath(file, { inputDir, outputDir });
    const output = await swc.transformFile(file, {
      sourceFileName: path.relative(path.dirname(outputPath), file),
      sourceMaps: "inline",
      module: {
        type: "commonjs",
      },
      jsc: {
        parser: {
          syntax: "typescript",
          decorators: true,
        },
        transform: {
          decoratorMetadata: true,
        },
      },
    });
    await writeToOut(file, output.code, {
      inputDir,
      outputDir,
      targetExtension: ".js",
    });
  } else if (!ignoreExtensions.some((ext) => file.endsWith(ext))) {
    // Copy non-ts files
    await copyToOut(file, { inputDir, outputDir });
  }
};

// Compile all files
await Promise.all(files.map(async (file) => medusaTransform(file)));

console.log(`Compiled all files in ${Date.now() - started}ms`);