CouchDB boolean filtering

Question

I am trying to work with CouchDB filtering but I can not understand how it works

So lets say, like the example they have:

function(doc, req){
    // we need only `mail` documents
    if (doc.type != 'mail'){
        return false;
    }
    // we're interested only in `new` ones
    if (doc.status != 'new'){
        return false;
    }
    return true; // passed!
}

I am bit confused because if I want to return only

mail documents

I think I should implement something like:

 if (doc.type == 'mail'){
        return true;
    }

At the end we have

return true //passed

but, is that mean that I will return all the documnents I have?

Hod · Accepted Answer · 2017-06-26T23:08:48.110

The example doesn't just filter for mail documents, it also requires they be new. Without the "new document check" you could just as well write the code as

function(doc, req){
  // we need only `mail` documents
  if (doc.type == 'mail') {
    return true;
  }

  return false;
}

The whole logic of the original, though, is implementing (in pseudo-code)

if (!mail document or !new document) then false
else true

CouchDB boolean filtering

1 Answers1