text: 'use strict';
  module.exports = ctx => ctx.fs.readFile('package.json').then(pkg => {
  	if (!pkg.main) {
  		return;
  	}
  
  	const fileName = ctx.files.find(file => file.toLowerCase().indexOf(pkg.main) === 0);
  
  	if (!fileName) {
  		ctx.report({
  			message: `Main file '${pkg.main}' does not exist.`,
  			file: ctx.fs.resolve('package.json')
  		});
  	}
  });
  