/**
* @internal
*
* Generates a fragment on the given type that fetches the minimal connection
* fields in order to merge different pagination results together at runtime.
*/
function generateConnectionFragment(
context: RelayCompilerContext,
type: GraphQLType,
): InlineFragment {
const compositeType = assertCompositeType(
RelaySchemaUtils.getNullableType((type: $FlowFixMe)),
);
const ast = GraphQL.parse(
`
fragment ConnectionFragment on ${String(compositeType)} {
${EDGES} {
${CURSOR}
${NODE} {
__typename # rely on GenerateRequisiteFieldTransform to add "id"
}
}
${PAGE_INFO} {
${END_CURSOR}
${HAS_NEXT_PAGE}
${HAS_PREV_PAGE}
${START_CURSOR}
}
}
`,
);
const fragmentAST = ast.definitions[0];
invariant(
fragmentAST && fragmentAST.kind === 'FragmentDefinition',
'RelayConnectionTransform: Expected a fragment definition AST.',
);
const fragment = RelayParser.transform(context.schema, fragmentAST);
invariant(
fragment && fragment.kind === 'Fragment',
'RelayConnectionTransform: Expected a connection fragment.',
);
return {
directives: [],
kind: 'InlineFragment',
metadata: null,
selections: fragment.selections,
typeCondition: compositeType,
};
}
definitions.forEach(definition => {
if (isOperationDefinitionAST(definition)) {
nodes.push(RelayParser.transform(schema, definition));
}
});