code: function isvalid(grunt, filepath, js) {
  	var config;
  	var syntax;
  	try {
  		config = { tolerant: true };
  		syntax = esprima.parse(js, config);
  		if (syntax.errors.length) {
  			syntax.errors.forEach(function(error) {
  				grunt.log.error(filepath, error.message);
  			});
  			return false;
  		}
  		return true;
  	} catch (exception) {
  		grunt.log.write('\n');
  		grunt.log.error(filepath, exception.message);
  		grunt.fail.errorcount++;
  		return false;
  	}
  }
docs: Private ..................................................................... 
  @param {Grunt} grunt
  @param {Array<string>} files
  @returns {boolean}
  
  function validate(grunt, longlist) {
  var filemap = mapcontents(grunt, longlist);
  return allvalid(grunt, filemap);
  }
  
  
  @param {Grunt} grunt
  @param {Array<string>} files
  @returns {boolean}
  
  function allvalid(grunt, files) {
  return Object.keys(files).every(function(filepath) {
  var js = files[filepath];
  return isvalid(grunt, js, filepath);
  });
  }
  
  
  @param {Grunt} grunt
  @param {string} js
  @param {string} filepath
  @returns {boolean}