Simple Metalsmith robots.txt plugin

build.js

import metalsmith from 'metalsmith';
import markdown from 'metalsmith-markdown';
import robots from './metalsmith-robots.js';

metalsmith(__dirname)
  .use(markdown())
  .use(robots({
    source: 'sample-robots.txt'
  })
  .destination('./build');

metalsmith-robots.js

export default function robots(opts) {
  return function(files, metalsmith, done) {
    fs.readFile(opts.source, function(err, data) {
      files['robots.txt'] = {
        contents: data
      };
      done();
    });
  };
}