anchor.diff:  
   Common options:
     -o <file> Generate the output into <file>.
  -  -c        Insert runtime type checks and enable assertions (checked mode).
     -m        Generate minified output.
     -h        Display this message (add -v for information about all options).''');
   }
  
positive.code:   --fast-startup
      Produce JavaScript that can be parsed more quickly by VMs. This option
      usually results in larger JavaScript files with faster startup.
      Note: the dart:mirrors library is not supported with this option.
  
    --preview-dart-2
      Preview of all Dart 2.0 semantics, this includes generic methods and strong
      mode type checks.
  
      This flag is mainly for early dogfooding and will be removed when all
      features are shipped.
  
  The following advanced options can help reduce the size of the generated code,
  but they may cause programs to behave unexpectedly if assumptions are not met.
  
negative.code: 
    Uri script = currentDirectory.resolve(arguments[0]);
    diagnosticHandler.autoReadFileUri = true;
    CompilerOptions compilerOptions = CompilerOptions.parse(options,
        libraryRoot: libraryRoot, platformBinaries: platformBinaries)
      ..entryPoint = script
  