Each one of the validate commands has a corresponding package building command that will get called on the source node as part of the validation cycle so that the appropriate data can get sent back to the node trying to validate the action. Instead of having to compile all this information yourself, Holochain provides a simple way to configure the package, by creating a PkgReq object.

A JavaScript ribosome package request function that indicates that the entire chain should be sent in the validation package, would look like this:

function validatePutPkg(entry_type) {
  var req = {};
  req[HC.PkgReq.Chain]=HC.PkgReq.ChainOpt.Full;
  return req;
}

Or, if all that's needed is the headers of entry types "foo" and "bar" the function would look like this:

function validatePutPkg(entry_type) {
  var req = {};
  req[HC.PkgReq.Chain]=HC.PkgReq.ChainOpt.Headers;
  req[HC.PkgReq.EntryTypes]=["foo","bar"];
  return req;
}

Or, if no extra data is needed, just return null. 

function validatePutPkg(entry_type) {
  return null;
}

Go back to the API documentation.