esbuild-plugin-extract-helpers/target/esm/index.mjs

Esbuild plugin to extract cjs helpers (like tslib)

// src/main/ts/plugin.ts
import path from "node:path";
import fs from "node:fs/promises";
import {
  transformFile,
  writeFiles,
  getOutputFiles,
  renderList,
  parseContentsLayout
} from "esbuild-plugin-utils";
var extractHelpersPlugin = (options = {}) => {
  return {
    name: "extract-helpers",
    setup(build) {
      const {
        absWorkingDir = process.cwd(),
        outdir,
        cwd = outdir || absWorkingDir,
        include = /./,
        exclude = /^$/,
        helper = "esblib.cjs"
      } = { ...build.initialOptions, ...options };
      const opts = {
        cwd,
        include,
        exclude,
        helper
      };
      build.onEnd(async (result) => onEnd(result, opts));
    }
  };
};
var onEnd = async (result, opts) => {
  const outputFiles = await getOutputFiles(result.outputFiles, opts.cwd);
  const helpers = /* @__PURE__ */ new Map();
  const helperRe = /^var (__\w+) = /;
  const hook = {
    on: "end",
    pattern: opts.include,
    // eslint-disable-next-line sonarjs/cognitive-complexity
    transform(c, p) {
      const { lines, header, body } = parseContentsLayout(c.trim());
      const headerSize = header ? header.split("\n").length : 0;
      const output = [];
      const helperPath = getRelativePath(opts.cwd, p, opts.helper);
      const capture = () => {
        helpers.set(ref, helper);
        helper = "";
        ref = "";
      };
      let refs = [];
      let helper = "";
      let ref = "";
      for (const line of lines.slice(headerSize)) {
        if (ref) {
          helper += line + "\n";
          if (line.endsWith(";") && !line.startsWith(" ")) capture();
        } else {
          const match = helperRe.exec(line);
          if (match) {
            ref = match[1];
            refs.push(ref);
            helper = line + "\n";
            if (line.endsWith(";")) capture();
          } else {
            output.push(line);
          }
        }
      }
      if (refs.length === 0) return c;
      refs = refs.filter((r) => output.some((l) => l.includes(r)));
      return formatFile(header, output, refs, helperPath);
    }
  };
  const transformedFiles = (await Promise.all(outputFiles.map(async (file) => transformFile(file, [hook], opts.cwd)))).filter(Boolean);
  await writeFiles(transformedFiles);
  await fs.writeFile(path.join(opts.cwd, opts.helper), formatHelpers(helpers), "utf-8");
};
var getRelativePath = (from, to, ref) => {
  const link = path.relative(from, path.join(path.dirname(to), ref));
  return link.startsWith(".") ? link : "./" + link;
};
var formatHelpers = (helpers) => `
${[...helpers.values()].join("\n")}
module.exports = {
${renderList([...helpers.keys()])}
};
`;
var formatFile = (header, lines, refs, helperPath) => {
  const body = lines.join("\n");
  const helpers = `const {
${renderList(refs)}
} = require('${helperPath}');
`;
  return [
    header,
    helpers,
    body
  ].filter(Boolean).join("\n");
};
export {
  extractHelpersPlugin as default,
  extractHelpersPlugin,
  formatFile,
  formatHelpers,
  getRelativePath,
  onEnd
};