GraphQL Fragments

Tools for dealing with GraphQL fragments.

Installing

npm install -S graphql-fragments

Usage

import Fragment from 'graphql-fragments';
import gql from 'grapqhl-tag';

const fragmentDoc = gql`
  fragment Foo on Bar {
    field1
    field2
    ...SubFragment
  }
`;

// subFragment is the Fragment which defines `SubFragment` above
const fragment = new Fragment(fragmentDoc, subFragment);

API

fragment.fragments()

Return a list of fragment documents, suitable to be passed into client.watchQuery

fragment.filter(data);

Assuming that data is of the type this fragment applies to, and is the result of a query that includes this fragment, filter out only the fields of data that are defined by this fragment.

fragment.check(data)

Throw an error if data does not include all the fields that this fragment defines.

fragment.propType

A function, much like fragment.check, suitable to be used by in a React propTypes check.

Caveats

As we cannot know if a conditional sub-fragment should apply, we take a conservative approach:

• when checking we do not error if fields from a conditional sub-fragment are missing
• when filtering, we take sub fields from conditional sub-fragments where possible.