GraphQL-tag always uses default value

Question

Can anyone explain me why my graphQL query always uses default values even if I specified my own value for this argument?

const FEED_QUERY2 = gql`
    query FEED_QUERY2($category : String = "NoPosts")
    {
        feed2(filter:  $category ) {
            blogposts {
                id
                name
                categories {
                    id
                    name
                }
            }
        }
    }
`

And am calling my query like this

import { Query } from 'react-apollo'
.
.
.
const category_string = "Python";
<Query query={FEED_QUERY2} category={category_string}>

Answer 1

category is not a valid prop for the Query component. The props available on the component are shown here in the docs. If you want to pass variables to your query, you should use the variables prop.

<Query query={FEED_QUERY2} variables={{category: category_string}}>