build.js

#!/usr/bin/env node
// Compresses the core Blockly files into a single JavaScript file.

const onlyUncompressed = process.argv.includes("--uncompressed");

const fs = require("fs");
const path = require("path");
const Compiler = require("google-closure-compiler").compiler;

const HEADER =
  "// Do not edit this file; automatically generated by build.js.\n'use strict';\n";
const CLOSURE_ROOT = "node_modules";
const CLOSURE_LIBRARY = "google-closure-library";

const LICENSE_RE =
  /\/\*\n\n [\w ]+\n\n Copyright \d+ Google Inc\.\n https:\/\/developers\.google\.com\/blockly\/\n\n Licensed under the Apache License, Version 2\.0 \(the "License"\);\n you may not use this file except in compliance with the License\.\n You may obtain a copy of the License at\n\n   http:\/\/www\.apache\.org\/licenses\/LICENSE-2\.0\n\n Unless required by applicable law or agreed to in writing, software\n distributed under the License is distributed on an "AS IS" BASIS,\n WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied\.\n See the License for the specific language governing permissions and\n limitations under the License\.\n\*\//g;

const toForward = (p) => p.replace(/\\/g, "/");

const findClosureBase = () => {
  const p = path.join(
    CLOSURE_ROOT,
    CLOSURE_LIBRARY,
    "closure",
    "goog",
    "base.js",
  );
  if (fs.existsSync(p)) return path.resolve(p);
  throw new Error("Closure base.js not found at " + p);
};

const runCompiler = (args) => {
  return new Promise((resolve, reject) => {
    const compiler = new Compiler(args);
    compiler.run((exitCode, stdout, stderr) => {
      if (exitCode === 0) {
        resolve(stdout);
      } else {
        reject(new Error(stderr || "Exit code " + exitCode));
      }
    });
  });
};

const writeFile = (target, code, remove) => {
  if (remove) code = code.replace(remove, "");
  code = code.replace(LICENSE_RE, "");
  code = HEADER + "\n" + code.trim();
  fs.writeFileSync(target, code, "utf8");
  console.log("SUCCESS: " + target);
};

const buildCompressedCore = () => {
  const target = "blockly_compressed_vertical.js";
  const closureDir = path.join(CLOSURE_ROOT, CLOSURE_LIBRARY);

  const args = [
    "--compilation_level=SIMPLE",
    "--language_in=ECMASCRIPT_2017",
    "--language_out=ECMASCRIPT5",
    "--rewrite_polyfills=false",
    "--define=goog.DEBUG=false",
    "--js=" + toForward(path.join(closureDir, "closure", "goog", "**.js")),
    "--js=" +
      toForward(
        path.join(closureDir, "third_party", "closure", "goog", "**.js"),
      ),
    "--js=core/**.js",
    "--entry_point=Blockly",
    "--dependency_mode=STRICT",
  ];

  return runCompiler(args).then((stdout) => {
    writeFile(target, stdout);
  });
};

const buildCompressedBlocks = (common) => {
  const target =
    (common ? "blocks_compressed" : "blocks_compressed_vertical") + ".js";
  const dir = common ? "blocks_common" : "blocks_vertical";

  const args = [
    "--compilation_level=SIMPLE",
    "--js=build/gen_blocks.js",
    "--js=core/colours.js",
    "--js=core/constants.js",
  ];

  fs.readdirSync(dir)
    .filter((f) => f.endsWith(".js"))
    .sort()
    .forEach((f) => {
      args.push("--js=" + path.join(dir, f).replace(/\\/g, "/"));
    });

  return runCompiler(args).then((stdout) => {
    writeFile(target, stdout, "var Blockly={Blocks:{}};");
  });
};

const buildUncompressed = () => {
  const target = "blockly_uncompressed_vertical.js";
  const closureBase = findClosureBase();
  const closureBaseDir = path.dirname(closureBase);
  const closureDir = "/node_modules";
  const closureLibrary = "google-closure-library";

  let content = HEADER + "\n";
  content += [
    "var isNodeJS = !!(typeof module !== 'undefined' && module.exports && typeof window === 'undefined');",
    "if (isNodeJS) {",
    "  var window = {};",
    '  require("' + closureDir + "/" + closureLibrary + '");',
    "}",
    "window.BLOCKLY_DIR = (function() {",
    "  if (!isNodeJS) {",
    "    var scripts = document.getElementsByTagName('script');",
    "    var re = /(.+)[\\\\/]blockly_uncompressed(_vertical|_horizontal|)\\.js$/;",
    "    for (var i = 0, script; script = scripts[i]; i++) {",
    "      var match = re.exec(script.src);",
    "      if (match) {",
    "        return match[1];",
    "      }",
    "    }",
    "  }",
    "  return '';",
    "})();",
    "window.BLOCKLY_BOOT = function() {",
    "  if (isNodeJS) {",
    '    require("' + closureDir + "/" + closureLibrary + '");',
    "  } else {",
    "    if (!window.goog) {",
    "      alert('Error: Closure not found.  Read this:\\n' +",
    "            'developers.google.com/blockly/guides/modify/web/closure');",
    "    }",
    "  }",
  ].join("\n");

  const coreFiles = fs
    .readdirSync("core")
    .filter((f) => f.endsWith(".js"))
    .sort();

  coreFiles.forEach((f) => {
    const fullPath = path.join("core", f);
    const relPath = path
      .relative(closureBaseDir, path.resolve(fullPath))
      .replace(/\\/g, "/");
    const src = fs.readFileSync(fullPath, "utf8");
    const provides = [];
    const requires = [];
    src.split("\n").forEach((line) => {
      let m;
      m = line.match(/^\s*goog\.provide\s*\(\s*['"](.+)['"]\s*\)/);
      if (m) provides.push(m[1]);
      m = line.match(/^\s*goog\.require\s*\(\s*['"](.+)['"]\s*\)/);
      if (m) requires.push(m[1]);
    });
    content +=
      '\ngoog.addDependency("' +
      relPath +
      '", ' +
      JSON.stringify(provides) +
      ", " +
      JSON.stringify(requires) +
      ");";
  });

  content += "\n\n// Load Blockly.\n";
  coreFiles.forEach((f) => {
    const fullPath = path.join("core", f);
    const src = fs.readFileSync(fullPath, "utf8");
    src.split("\n").forEach((line) => {
      const m = line.match(/^\s*goog\.provide\s*\(\s*['"](.+)['"]\s*\)/);
      if (m) content += "goog.require('" + m[1] + "');\n";
    });
  });

  content += "\n";
  content +=
    [
      "delete this.BLOCKLY_DIR;",
      "delete this.BLOCKLY_BOOT;",
      "};",
      "if (isNodeJS) {",
      "  window.BLOCKLY_BOOT();",
      "  module.exports = Blockly;",
      "} else {",
      "  document.write('<script>var goog = undefined;</script>');",
      "  document.write('<script src=\"' + window.BLOCKLY_DIR + '" +
        closureDir +
        "/" +
        closureLibrary +
        "/closure/goog/base.js\"></script>');",
      "  document.write('<script>window.BLOCKLY_BOOT();</script>');",
      "}",
    ].join("\n") + "\n";

  fs.writeFileSync(target, content, "utf8");
  console.log("SUCCESS: " + target);
};

const main = () => {
  console.log("Using local compiler: google-closure-compiler ...\n");
  const startTime = Date.now();

  runCompiler(["--compilation_level=SIMPLE", "--js=build/test_input.js"])
    .then((stdout) => {
      const expected = fs.readFileSync("build/test_expect.js", "utf8").trim();
      if (stdout.trim() !== expected) {
        throw new Error(
          'Compiler self-test failed.\nExpected: "' +
            expected +
            '"\nGot: "' +
            stdout.trim() +
            '"',
        );
      }
      console.log("Compiler self-test passed.\n");

      buildUncompressed();
      if (onlyUncompressed) return;

      return Promise.all([
        buildCompressedCore(),
        buildCompressedBlocks(false),
        buildCompressedBlocks(true),
      ]);
    })
    .then(() => {
      const endTime = Date.now();
      const duration = (endTime - startTime) / 1000;
      console.log("\nBuild complete in " + duration.toFixed(2) + " seconds.");
    })
    .catch((err) => {
      console.error("Build failed:", err.message);
      process.exit(1);
    });
};

main();