Tools: Hh_server
The Hack server works behind the scenes to keep your codebase in constant sync for the
hh_client typechecker. However, the serverhh_server can also be used for some primary standalone functionality as well.
If you want to see all the options available to
hh_server, see the help via hh_server --help.Check and Exit
If you want to typecheck a file or a directory of files without the overhead of a constant server running combined with
hh_client, you can do a quick and dirty check with hh_server.hh_server --check <path>
Like with running
hh_client, you must ensure that the root of your path has an empty .hhconfig file.
Specify a dot
. to represent checking the current path.Automatic Type Annotations
hh_server provides a mode where you can take a Hack file or project of Hack files and automatically add type annotations to those files.
NOTE: This only works on
<?hh files.hh_server --convert <path to files to convert> <path to top level of project>
Many times the two paths are the same. However, this does give you the flexibility of converting only a subset of a project. Normally, the path to the top level of the project has the
.hhconfig.
This process annotates with soft type hints via
@. This is because the annotation is far from perfect and we would rather have warnings thrown rather than fatal at runtime.
For example, the following unannotated Hack file:
<?hh
function foo($x) {
if ($x + 3 < 10) {
return false;
}
return true;
}
function bar($y) {
if ($y) {
return "Hi";
}
return null;
}
might be converted to:
<?hh
function foo($x): @bool {
if ($x + 3 < 10) {
return false;
}
return true;
}
function bar($y): @?string {
if ($y) {
return "Hi";
}
return null;
}
