code: function getContractNames(filePath){
    const names = [];
    const code = fs.readFileSync(filePath, 'utf-8');
    const ast = parser.parse(code, {tolerant: true});
  
    parser.visit(ast, {
      ContractDefinition: function(node) {
        names.push(node.name);
      }
    });
  
    return names;
  }
docs: Parses files for contract names
  @param  {String} filePath path to file
  @return {Array}           array of contract names