understanding _ in resolve function in new GraphQLObjectType

[webmobiles]

what does mean '_' parameter in resolve function ?. what is it for ?where i can read documentation about resolve parameters?

 const queryType = new GraphQLObjectType({
        name: 'RootQuery',
        fields: {
            usersCount: {
                type: GraphQLInt,
                resolve: (_, args, { db }) =>
                    db.collection('users').count()
            }
        }
    });

[papandreou]

It means "don't care"/"anonymous parameter". Since the first argument is not actually used by the function, don't bother assigning a proper name to it.

Related discussion: #844

[webmobiles]

Thanks !