index.js

'use strict';

var through = require('through2'),
    glob = require('glob'),
    path = require('path'),
    replaceExt = require('replace-ext'),
    gutil = require('gulp-util'),
    fs = require('fs'),
    PluginError = gutil.PluginError;

var PLUGIN_NAME = 'gulp-include-source';

var placeholders = {
  'js' : '<script src="%"></script>',
  'css' : '<link rel="stylesheet" href="%">'
};

function matchExpressions(contents) {
  return contents.match(/<!--\s+include:([a-z]+)\(([^)]+)\)\s+-->/);
}

function replaceExtension(filename, type, options) {

  if( options.scriptExt && type === 'js' ) {
    filename = replaceExt(filename, '.' + options.scriptExt);
  } else if( options.styleExt && type === 'css' ) {
    filename = replaceExt(filename, '.' + options.styleExt);
  }

  return filename;
}

function parseFiles(source, cwd) {

  if( source.indexOf('list:') === 0 ) {
    var cleanSrc = source.replace('list:', '');
    return fs.readFileSync( cleanSrc ).toString().split('\n');
  }

  return glob.sync( source, { cwd : cwd } );
}

function injectFiles(file, options) {

  var contents = file.contents.toString();
  var cwd = options.cwd || path.dirname(file.path);
  var matches = matchExpressions(contents);

  while( matches ) {

    var type = matches[1];
    var placeholder = placeholders[ type ];
    var files = parseFiles(matches[2], cwd);
    var includes = '';

    if( placeholder && files && files.length > 0 ) {

      includes = files.map(function(filename) {
        filename = replaceExtension(filename, type, options);
        return placeholder.split('%').join(filename);
      }).join('\n');
    }

    contents = contents.substring(0, matches.index) + includes + contents.substring(matches.index + matches[0].length);
    matches = matchExpressions(contents);
  }

  return contents;
}

function gulpIncludeSource(options) {

  options = options || {};

  var stream = through.obj(function(file, enc, callback) {

    if (file.isNull()) {
      this.push(file); // Do nothing if no contents
      return callback();
    }

    if (file.isStream()) {
      this.emit('error', new PluginError(PLUGIN_NAME, 'Streaming not supported!'));
      return callback();
    }

    if (file.isBuffer()) {
      try {
        file.contents = new Buffer( injectFiles( file, options ) );
      } catch (err) {
        this.emit('error', new gutil.PluginError(PLUGIN_NAME, err));
      }
    }

    this.push(file);
    return callback();
  });

  return stream;
}

module.exports = gulpIncludeSource;