Gulpfile.js

"use strict";

const plumber = require("gulp-plumber");
const through = require("through2");
const chalk = require("chalk");
const newer = require("gulp-newer");
const babel = require("gulp-babel");
const gulpWatch = require("gulp-watch");
const fancyLog = require("fancy-log");
const filter = require("gulp-filter");
const gulp = require("gulp");
const path = require("path");
const rollup = require("rollup");
const rollupAlias = require("@rollup/plugin-alias");
const rollupBabel = require("rollup-plugin-babel");
const rollupBabelSource = require("./scripts/rollup-plugin-babel-source");
const rollupCommonJs = require("rollup-plugin-commonjs");
const rollupJson = require("@rollup/plugin-json");
const rollupNodeBuiltins = require("rollup-plugin-node-builtins");
const rollupNodeGlobals = require("rollup-plugin-node-globals");
const rollupNodeResolve = require("rollup-plugin-node-resolve");
const rollupReplace = require("rollup-plugin-replace");
const { terser: rollupTerser } = require("rollup-plugin-terser");

const defaultSourcesGlob = "./@(codemods|packages|eslint)/*/src/**/*.js";

function swapSrcWithLib(srcPath) {
  const parts = srcPath.split(path.sep);
  parts[2] = "lib";
  return parts.join(path.sep);
}

function getIndexFromPackage(name) {
  return `${name}/src/index.js`;
}

function compilationLogger() {
  return through.obj(function(file, enc, callback) {
    fancyLog(`Compiling '${chalk.cyan(file.relative)}'...`);
    callback(null, file);
  });
}

function errorsLogger() {
  return plumber({
    errorHandler(err) {
      fancyLog(err.stack);
    },
  });
}

function rename(fn) {
  return through.obj(function(file, enc, callback) {
    file.path = fn(file);
    callback(null, file);
  });
}

function buildBabel(exclude, sourcesGlob = defaultSourcesGlob) {
  const base = __dirname;

  let stream = gulp.src(sourcesGlob, { base: __dirname });

  if (exclude) {
    const filters = exclude.map(p => `!**/${p}/**`);
    filters.unshift("**");
    stream = stream.pipe(filter(filters));
  }

  return stream
    .pipe(errorsLogger())
    .pipe(newer({ dest: base, map: swapSrcWithLib }))
    .pipe(compilationLogger())
    .pipe(babel())
    .pipe(
      // Passing 'file.relative' because newer() above uses a relative
      // path and this keeps it consistent.
      rename(file => path.resolve(file.base, swapSrcWithLib(file.relative)))
    )
    .pipe(gulp.dest(base));
}

let babelVersion = require("./packages/babel-core/package.json").version;
function buildRollup(packages) {
  const sourcemap = process.env.NODE_ENV === "production";
  const minify = !!process.env.IS_PUBLISH;
  return Promise.all(
    packages.map(async ({ src, format, dest, name, filename, version }) => {
      // TODO: Node 6 doesn't support default values in shorthand properties in
      // object destructuring in async function parameters
      if (version === undefined) version = babelVersion;

      const extraPlugins = [];
      let inputExternal = undefined,
        outputGlobals = undefined,
        nodeResolveBrowser = false,
        babelEnvName = "rollup";
      switch (src) {
        case "packages/babel-standalone":
          nodeResolveBrowser = true;
          babelEnvName = "standalone";
          if (minify) {
            extraPlugins.push(
              rollupTerser({
                include: /^.+\.min\.js$/,
              })
            );
          }
          break;
        case "packages/babel-preset-env-standalone":
          nodeResolveBrowser = true;
          babelEnvName = "standalone";
          if (minify) {
            extraPlugins.push(
              rollupTerser({
                include: /^.+\.min\.js$/,
              })
            );
          }
          inputExternal = ["@babel/standalone"];
          outputGlobals = {
            "@babel/standalone": "Babel",
          };
          extraPlugins.push(
            rollupAlias({
              entries: [
                {
                  find: "./available-plugins",
                  replacement: require.resolve(
                    path.join(__dirname, src, "./src/available-plugins")
                  ),
                },
                {
                  find: "caniuse-lite/data/regions",
                  replacement: require.resolve(
                    path.join(__dirname, src, "./src/caniuse-lite-regions")
                  ),
                },
              ],
            })
          );
          break;
      }
      // If this build is part of a pull request, include the pull request number in
      // the version number.
      if (process.env.CIRCLE_PR_NUMBER) {
        const prVersion = "+pr." + process.env.CIRCLE_PR_NUMBER;
        babelVersion += prVersion;
        version += prVersion;
      }
      const input = getIndexFromPackage(src);
      fancyLog(`Compiling '${chalk.cyan(input)}' with rollup ...`);

      const bundle = await rollup.rollup({
        input,
        external: inputExternal,
        plugins: [
          ...extraPlugins,
          rollupBabelSource(),
          rollupReplace({
            "process.env.NODE_ENV": JSON.stringify(process.env.NODE_ENV),
            BABEL_VERSION: JSON.stringify(babelVersion),
            VERSION: JSON.stringify(version),
          }),
          rollupBabel({
            envName: babelEnvName,
            babelrc: false,
            extends: "./babel.config.js",
          }),
          rollupNodeResolve({
            browser: nodeResolveBrowser,
            preferBuiltins: true,
            //todo: When Yarn workspaces is enabled, remove `dedupe` option
            dedupe(importee) {
              return (
                importee.startsWith("lodash/") ||
                [
                  "babel-plugin-dynamic-import-node/utils",
                  "esutils",
                  "semver",
                  "source-map",
                ].includes(importee)
              );
            },
          }),
          rollupCommonJs({
            include: [
              /node_modules/,
              "packages/babel-preset-env/data/**",
              "packages/babel-runtime/regenerator/**",
            ],
            namedExports: {
              "babel-plugin-dynamic-import-node/utils.js": [
                "createDynamicImportTransform",
                "getImportSource",
              ],
              "@babel/standalone": ["availablePlugins", "registerPlugin"],
            },
          }),
          rollupJson(),
          rollupNodeBuiltins(),
          rollupNodeGlobals({ sourceMap: sourcemap }),
        ],
      });

      const outputFile = path.resolve(src, dest, filename || "index.js");
      await bundle.write({
        file: outputFile,
        format,
        name,
        globals: outputGlobals,
        sourcemap: sourcemap,
      });

      if (!process.env.IS_PUBLISH) {
        fancyLog(
          chalk.yellow(
            `Skipped minification of '${chalk.cyan(
              path.relative(path.join(__dirname, ".."), outputFile)
            )}' because not publishing`
          )
        );
        return undefined;
      }
      fancyLog(
        `Minifying '${chalk.cyan(
          path.relative(path.join(__dirname, ".."), outputFile)
        )}'...`
      );

      await bundle.write({
        file: outputFile.replace(/\.js$/, ".min.js"),
        format,
        name,
        globals: outputGlobals,
        sourcemap: sourcemap,
      });
    })
  );
}

const libBundles = [
  {
    src: "packages/babel-parser",
    format: "cjs",
    dest: "lib",
    version: require("./packages/babel-parser/package").version,
  },
];

const standaloneBundle = [
  {
    src: "packages/babel-standalone",
    format: "umd",
    name: "Babel",
    filename: "babel.js",
    dest: "",
    version: require("./packages/babel-core/package").version,
  },
];

const presetEnvStandaloneBundle = [
  {
    src: "packages/babel-preset-env-standalone",
    format: "umd",
    name: "BabelPresetEnv",
    filename: "babel-preset-env.js",
    dest: "",
    version: require("./packages/babel-preset-env/package").version,
  },
];

gulp.task("build-rollup", () => buildRollup(libBundles));
gulp.task("build-babel-standalone", () => buildRollup(standaloneBundle));

gulp.task("build-babel-preset-env-standalone", () =>
  buildRollup(presetEnvStandaloneBundle)
);

gulp.task("build-babel", () => buildBabel(/* exclude */ libBundles));
gulp.task("build-babel-types", () =>
  buildBabel(/* exclude */ libBundles, "packages/babel-types/src/**/*.js")
);
gulp.task("build", gulp.parallel("build-rollup", "build-babel"));

gulp.task("default", gulp.series("build"));

gulp.task("build-no-bundle", () => buildBabel());

gulp.task(
  "watch",
  gulp.series("build-no-bundle", function watch() {
    gulpWatch(
      defaultSourcesGlob,
      { debounceDelay: 200 },
      gulp.task("build-no-bundle")
    );
  })
);