gulp-usemin-extend/lib/blocksBuilder.js

Replaces references to non-optimized scripts or stylesheets into a set of HTML files (or any templates/views).

var fs = require('fs');
var glob = require('glob');
var path = require('path');
var gutil = require('gulp-util');

module.exports = function(file, options) {
  options = options || {};

  var startReg = options.startReg || /<!--\s*build:(\w+)(?:(?:\(([^\)]+?)\))?\s+(\/?([^\s]+?))?)?\s*-->/gim;
  var endReg = options.endReg || /<!--\s*endbuild\s*-->/gim;
  var jsReg = options.jsReg || /<\s*script\s+.*?src\s*=\s*['"]?([^'"?# ]+).*?><\s*\/\s*script\s*>/gi;
  var cssReg = options.cssReg || /<\s*link\s+.*?href\s*=\s*['"]?([^'"?# ]+).*?>/gi;
  var cssMediaReg = /<\s*link\s+.*?media\s*=\s*['"]?([^'" ]+).*?>/gi;
  var startCondReg = /<!--\[[^\]]+\]>/gim;
  var endCondReg = /<!\[endif\]-->/gim;

  var basePath = file.base;
  var mainPath = path.dirname(file.path);
  var outputPath = options.outputRelativePath || '';
  var content = String(file.contents);
  var sections = content.split(endReg);
  var blocks = [];
  var cssMediaQuery = null;

  function getFiles(content, reg, alternatePath) {
    var paths = [];
    var files = [];
    cssMediaQuery = null;
    content
      .replace(startCondReg, '')
      .replace(endCondReg, '')
      .replace(/<!--(?:(?:.|\r|\n)*?)-->/gim, function (a) {
        return options.enableHtmlComment ? a : '';
      })
      .replace(reg, function (a, b) {
        var filePath = path.resolve(path.join(
          alternatePath || options.path || mainPath,
          b.replace(/^'|^"/, '').replace(/'$/, '').replace(/"$/, '')
        ));

        if (options.assetsDir)
          filePath = path.resolve(path.join(options.assetsDir, path.relative(basePath, filePath)));

        paths.push(filePath);
      });

    if (reg === cssReg) {
      content.replace(cssMediaReg, function(a, media) {
        media = media.replace(/^'|^"/, '').replace(/'$/, '').replace(/"$/, '');

        if (!cssMediaQuery) {
          cssMediaQuery = media;
        } else {
          if (cssMediaQuery != media)
            throw new gutil.PluginError('gulp-usemin', 'incompatible css media query for ' + a + ' detected.');
        }
      });
    }

    for (var i = 0, l = paths.length; i < l; ++i) {
      var filepaths = glob.sync(paths[i]);
      if(filepaths[0] === undefined) {
        throw new gutil.PluginError('gulp-usemin', 'Path ' + paths[i] + ' not found!');
      }
      filepaths.forEach(function (filepath) {
        files.push(new gutil.File({
          path: filepath,
          contents: fs.readFileSync(filepath)
        }));
      });
    }

    return files;
  }

  for (var i = 0, l = sections.length; i < l; ++i) {
    if (sections[i].match(startReg)) {
      var section = sections[i].split(startReg);
      blocks.push(section[0]);

      var startCondLine = section[5].match(startCondReg);
      var endCondLine = section[5].match(endCondReg);
      if (startCondLine && endCondLine)
        blocks.push(startCondLine[0]);

      if (section[1] !== 'remove') {
        if(section[1] === 'htmlimport'){
          blocks.push({
            type: 'htmlimport',
            nameInHTML: section[3],
            name: path.join(outputPath || path.relative(basePath, mainPath), section[4]),
            files: getFiles(section[5], cssReg, section[2]),
            tasks: options[section[1]]
          });

        }else if (jsReg.test(section[5])) {
          if (section[1].indexOf('inline') !== -1) {
            blocks.push({
              type: 'inlinejs',
              files: getFiles(section[5], jsReg, section[2]),
              tasks: options[section[1]]
            });
          }
          else {
            blocks.push({
              type: 'js',
              nameInHTML: section[3],
              name: path.join(outputPath || path.relative(basePath, mainPath), section[4]),
              files: getFiles(section[5], jsReg, section[2]),
              tasks: options[section[1]]
            });
          }

        }
        else {
          if (section[1].indexOf('inline') !== -1) {
            blocks.push({
              type: 'inlinecss',
              files: getFiles(section[5], cssReg, section[2]),
              tasks: options[section[1]],
              mediaQuery: cssMediaQuery
            });
          }
          else {
            blocks.push({
              type: 'css',
              nameInHTML: section[3],
              name: path.join(outputPath || path.relative(basePath, mainPath), section[4]),
              files: getFiles(section[5], cssReg, section[2]),
              tasks: options[section[1]],
              mediaQuery: cssMediaQuery
            });
          }
        }
      }

      if (startCondLine && endCondLine)
        blocks.push(endCondLine[0]);
    } else
      blocks.push(sections[i]);
  }

  return blocks;
};