html-minifier-next/cli.js

Highly configurable, well-tested, JavaScript-based HTML minifier.

#!/usr/bin/env node
/**
 * html-minifier-next CLI tool
 *
 * The MIT License (MIT)
 *
 *  Copyright (c) 2014-2016 Zoltan Frombach
 *
 *  Permission is hereby granted, free of charge, to any person obtaining a copy of
 *  this software and associated documentation files (the "Software"), to deal in
 *  the Software without restriction, including without limitation the rights to
 *  use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 *  the Software, and to permit persons to whom the Software is furnished to do so,
 *  subject to the following conditions:
 *
 *  The above copyright notice and this permission notice shall be included in all
 *  copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 *  FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 *  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 *  IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 *  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

import fs from 'fs';
import path from 'path';
import { createRequire } from 'module';
import { camelCase, paramCase } from 'change-case';
import { Command } from 'commander';
import { minify } from './src/htmlminifier.js';

const require = createRequire(import.meta.url);

const pkg = require('./package.json');

const program = new Command();
program.name(pkg.name);
program.version(pkg.version);

function fatal(message) {
  console.error(message);
  process.exit(1);
}

/**
 * JSON does not support regexes, so, e.g., JSON.parse() will not create
 * a RegExp from the JSON value `[ "/matchString/" ]`, which is
 * technically just an array containing a string that begins and end with
 * a forward slash. To get a RegExp from a JSON string, it must be
 * constructed explicitly in JavaScript.
 *
 * The likelihood of actually wanting to match text that is enclosed in
 * forward slashes is probably quite rare, so if forward slashes were
 * included in an argument that requires a regex, the user most likely
 * thought they were part of the syntax for specifying a regex.
 *
 * In the unlikely case that forward slashes are indeed desired in the
 * search string, the user would need to enclose the expression in a
 * second set of slashes:
 *
 *    --customAttrSrround "[\"//matchString//\"]"
 */
function parseRegExp(value) {
  if (value) {
    return new RegExp(value.replace(/^\/(.*)\/$/, '$1'));
  }
}

function parseJSON(value) {
  if (value) {
    try {
      return JSON.parse(value);
    } catch {
      if (/^{/.test(value)) {
        fatal('Could not parse JSON value \'' + value + '\'');
      }
      return value;
    }
  }
}

function parseJSONArray(value) {
  if (value) {
    value = parseJSON(value);
    return Array.isArray(value) ? value : [value];
  }
}

function parseJSONRegExpArray(value) {
  value = parseJSONArray(value);
  return value && value.map(parseRegExp);
}

const parseString = value => value;

const mainOptions = {
  caseSensitive: 'Treat attributes in case-sensitive manner (useful for custom HTML elements)',
  collapseBooleanAttributes: 'Omit attribute values from boolean attributes',
  customFragmentQuantifierLimit: ['Set maximum quantifier limit for custom fragments to prevent ReDoS attacks (default: 200)', parseInt],
  collapseInlineTagWhitespace: 'Don’t leave any spaces between “display: inline;” elements when collapsing—use with “collapseWhitespace=true”',
  collapseWhitespace: 'Collapse whitespace that contributes to text nodes in a document tree',
  conservativeCollapse: 'Always collapse to 1 space (never remove it entirely)—use with “collapseWhitespace=true”',
  continueOnParseError: 'Handle parse errors instead of aborting',
  customAttrAssign: ['Arrays of regexes that allow to support custom attribute assign expressions (e.g., “<div flex?="{{mode != cover}}"></div>”)', parseJSONRegExpArray],
  customAttrCollapse: ['Regex that specifies custom attribute to strip newlines from (e.g., /ng-class/)', parseRegExp],
  customAttrSurround: ['Arrays of regexes that allow to support custom attribute surround expressions (e.g., “<input {{#if value}}checked="checked"{{/if}}>”)', parseJSONRegExpArray],
  customEventAttributes: ['Arrays of regexes that allow to support custom event attributes for minifyJS (e.g., “ng-click”)', parseJSONRegExpArray],
  decodeEntities: 'Use direct Unicode characters whenever possible',
  html5: 'Parse input according to the HTML specification',
  ignoreCustomComments: ['Array of regexes that allow to ignore certain comments, when matched', parseJSONRegExpArray],
  ignoreCustomFragments: ['Array of regexes that allow to ignore certain fragments, when matched (e.g., “<?php … ?>”, “{{ … }}”)', parseJSONRegExpArray],
  includeAutoGeneratedTags: 'Insert elements generated by HTML parser',
  inlineCustomElements: ['Array of names of custom elements which are inline', parseJSONArray],
  keepClosingSlash: 'Keep the trailing slash on void elements',
  maxInputLength: ['Maximum input length to prevent ReDoS attacks', parseInt],
  maxLineLength: ['Specify a maximum line length; compressed output will be split by newlines at valid HTML split-points', parseInt],
  minifyCSS: ['Minify CSS in “style” elements and “style” attributes (uses clean-css)', parseJSON],
  minifyJS: ['Minify JavaScript in “script” elements and event attributes (uses Terser)', parseJSON],
  minifyURLs: ['Minify URLs in various attributes (uses relateurl)', parseJSON],
  noNewlinesBeforeTagClose: 'Never add a newline before a tag that closes an element',
  preserveLineBreaks: 'Always collapse to 1 line break (never remove it entirely) when whitespace between tags includes a line break—use with “collapseWhitespace=true”',
  preventAttributesEscaping: 'Prevents the escaping of the values of attributes',
  processConditionalComments: 'Process contents of conditional comments through minifier',
  processScripts: ['Array of strings corresponding to types of “script” elements to process through minifier (e.g., “text/ng-template”, “text/x-handlebars-template”, etc.)', parseJSONArray],
  quoteCharacter: ['Type of quote to use for attribute values (“\'” or “"”)', parseString],
  removeAttributeQuotes: 'Remove quotes around attributes when possible',
  removeComments: 'Strip HTML comments',
  removeEmptyAttributes: 'Remove all attributes with whitespace-only values',
  removeEmptyElements: 'Remove all elements with empty contents',
  removeOptionalTags: 'Remove unrequired tags',
  removeRedundantAttributes: 'Remove attributes when value matches default',
  removeScriptTypeAttributes: 'Remove “type="text/javascript"” from “script” elements; other “type” attribute values are left intact',
  removeStyleLinkTypeAttributes: 'Remove “type="text/css"” from “style” and “link” elements; other “type” attribute values are left intact',
  removeTagWhitespace: 'Remove space between attributes whenever possible; note that this will result in invalid HTML',
  sortAttributes: 'Sort attributes by frequency',
  sortClassName: 'Sort style classes by frequency',
  trimCustomFragments: 'Trim whitespace around “ignoreCustomFragments”',
  useShortDoctype: 'Replaces the doctype with the short (HTML) doctype'
};

// Configure command line flags
const mainOptionKeys = Object.keys(mainOptions);
mainOptionKeys.forEach(function (key) {
  const option = mainOptions[key];
  if (Array.isArray(option)) {
    key = key === 'minifyURLs' ? '--minify-urls' : '--' + paramCase(key);
    key += option[1] === parseJSON ? ' [value]' : ' <value>';
    program.option(key, option[0], option[1]);
  } else if (~['html5', 'includeAutoGeneratedTags'].indexOf(key)) {
    program.option('--no-' + paramCase(key), option);
  } else {
    program.option('--' + paramCase(key), option);
  }
});
program.option('-o --output <file>', 'Specify output file (if not specified STDOUT will be used for output)');

function readFile(file) {
  try {
    return fs.readFileSync(file, { encoding: 'utf8' });
  } catch (e) {
    fatal('Cannot read ' + file + '\n' + e.message);
  }
}

let config = {};
program.option('-c --config-file <file>', 'Use config file', function (configPath) {
  const data = readFile(configPath);
  try {
    config = JSON.parse(data);
  } catch (je) {
    try {
      config = require(path.resolve(configPath));
    } catch (ne) {
      fatal('Cannot read the specified config file.\nAs JSON: ' + je.message + '\nAs module: ' + ne.message);
    }
  }
  mainOptionKeys.forEach(function (key) {
    if (key in config) {
      const option = mainOptions[key];
      if (Array.isArray(option)) {
        const value = config[key];
        config[key] = option[1](typeof value === 'string' ? value : JSON.stringify(value));
      }
    }
  });

  // Handle fileExt in config file
  if ('fileExt' in config) {
    // Support both string (`html,htm`) and array (`["html", "htm"]`) formats
    if (Array.isArray(config.fileExt)) {
      config.fileExt = config.fileExt.join(',');
    }
  }
});
program.option('--input-dir <dir>', 'Specify an input directory');
program.option('--output-dir <dir>', 'Specify an output directory');
program.option('--file-ext <extensions>', 'Specify file extension(s) to process (comma-separated), e.g., “html” or “html,htm,php”');

let content;
program.arguments('[files...]').action(function (files) {
  content = files.map(readFile).join('');
}).parse(process.argv);

const programOptions = program.opts();

function createOptions() {
  const options = {};

  mainOptionKeys.forEach(function (key) {
    const param = programOptions[key === 'minifyURLs' ? 'minifyUrls' : camelCase(key)];

    if (typeof param !== 'undefined') {
      options[key] = param;
    } else if (key in config) {
      options[key] = config[key];
    }
  });
  return options;
}

function mkdir(outputDir, callback) {
  fs.mkdir(outputDir, { recursive: true }, function (err) {
    if (err) {
      fatal('Cannot create directory ' + outputDir + '\n' + err.message);
    }
    callback();
  });
}

function processFile(inputFile, outputFile) {
  fs.readFile(inputFile, { encoding: 'utf8' }, async function (err, data) {
    if (err) {
      fatal('Cannot read ' + inputFile + '\n' + err.message);
    }
    let minified;
    try {
      minified = await minify(data, createOptions());
    } catch (e) {
      fatal('Minification error on ' + inputFile + '\n' + e.message);
    }
    fs.writeFile(outputFile, minified, { encoding: 'utf8' }, function (err) {
      if (err) {
        fatal('Cannot write ' + outputFile + '\n' + err.message);
      }
    });
  });
}

function parseFileExtensions(fileExt) {
  if (!fileExt) return [];
  const list = fileExt
    .split(',')
    .map(ext => ext.trim().replace(/^\.+/, '').toLowerCase())
    .filter(ext => ext.length > 0);
  return [...new Set(list)];
}

function shouldProcessFile(filename, fileExtensions) {
  if (!fileExtensions || fileExtensions.length === 0) {
    return true; // No extensions specified, process all files
  }

  const fileExt = path.extname(filename).replace(/^\.+/, '').toLowerCase();
  return fileExtensions.includes(fileExt);
}

function processDirectory(inputDir, outputDir, extensions) {
  // If first call provided a string, normalize once; otherwise assume pre-parsed array
  if (typeof extensions === 'string') {
    extensions = parseFileExtensions(extensions);
  }

  fs.readdir(inputDir, function (err, files) {
    if (err) {
      fatal('Cannot read directory ' + inputDir + '\n' + err.message);
    }

    files.forEach(function (file) {
      const inputFile = path.join(inputDir, file);
      const outputFile = path.join(outputDir, file);

      fs.stat(inputFile, function (err, stat) {
        if (err) {
          fatal('Cannot read ' + inputFile + '\n' + err.message);
        } else if (stat.isDirectory()) {
          processDirectory(inputFile, outputFile, extensions);
        } else if (shouldProcessFile(file, extensions)) {
          mkdir(outputDir, function () {
            processFile(inputFile, outputFile);
          });
        }
      });
    });
  });
}

const writeMinify = async () => {
  const minifierOptions = createOptions();
  let minified;

  try {
    minified = await minify(content, minifierOptions);
  } catch (e) {
    fatal('Minification error:\n' + e.message);
  }

  let stream = process.stdout;

  if (programOptions.output) {
    stream = fs.createWriteStream(programOptions.output)
      .on('error', (e) => {
        fatal('Cannot write ' + programOptions.output + '\n' + e.message);
      });
  }

  stream.write(minified);
};

const { inputDir, outputDir, fileExt } = programOptions;

// Resolve file extensions: CLI argument takes priority over config file, even if empty string
const hasCliFileExt = program.getOptionValueSource('fileExt') === 'cli';
const resolvedFileExt = hasCliFileExt ? fileExt : config.fileExt;

if (inputDir || outputDir) {
  if (!inputDir) {
    fatal('The option output-dir needs to be used with the option input-dir. If you are working with a single file, use -o.');
  } else if (!outputDir) {
    fatal('You need to specify where to write the output files with the option --output-dir');
  }
  processDirectory(inputDir, outputDir, resolvedFileExt);
} else if (content) { // Minifying one or more files specified on the CMD line
  writeMinify();
} else { // Minifying input coming from STDIN
  content = '';
  process.stdin.setEncoding('utf8');
  process.stdin.on('data', function (data) {
    content += data;
  }).on('end', writeMinify);
}