Grunt partials injection task

Gruntfile.js

'use strict';

// Replace html comment tag by content of file, e.g:
// e.g: "<!-- partial: partials/header.html -->" will be replaced by the content of "partials/header.html"
// Then using grunt in command line: "grunt partials"
// Not the best idea ever, but when you have sometimes restriction or to simulate server-side SSI (Server Side Includes), that can be useful.

module.exports = function (grunt) {
  grunt.initConfig({
    partials: {
      options: {
        files: ['my-directory/index.html']
      }
    }
  });
  
  // Replace html comments by its partials
  grunt.registerTask('partials', 'Inject partials to defined files', function() {
    var options = this.options();

    if (!options.files.length) {
      grunt.log.warn('No files defined.');
      return false;
    }

    // Tag pattern
    var pattern = '<!-- partial: ([^ ]+) -->';

    // Fetch every tags and associate with its content
    options.files
      .forEach(function (filepath) {

        grunt.log.writeln('Injecting partials into ' + filepath);

        var file = grunt.file.read(filepath);
        if (file.length < 1 ) {
          grunt.log.warn('File was empty?');
        }

        var tags = file.match(new RegExp(pattern, 'gi'));

        tags.forEach(function (tag) {
          grunt.log.write('Replacing ' + tag + '...');

          var partialPath = (new RegExp(pattern, 'g')).exec(tag);

          if (partialPath) {
            var partial = grunt.file.read(partialPath[1]);
            file = file.replace(partialPath[0], partial);

            grunt.log.ok();
          } else {
            grunt.log.error();
          }
        });

        grunt.file.write(filepath, file);

        grunt.log.ok('Done ' + filepath);
    });
  });
  
  grunt.registerTask('partials', ['partials']);
};