Checking document for other fragment definitions

Its possible that fragments have already been defined in the document itself - we want to check against those to make sure we’re only attaching fragments that either
1) don’t already exist in the document
2) are distinct in the fragments to be attached to the document

src/queries/getFromAST.ts

@@ -7,6 +7,7 @@ import {
 import assign = require('lodash.assign');
 import countBy = require('lodash.countby');
 import identity = require('lodash.identity');
+import includes = require('lodash.includes');
 import uniq = require('lodash.uniq');
 
 export function getMutationDefinition(doc: Document): OperationDefinition {
@@ -154,7 +155,14 @@ export function addFragmentsToDocument(queryDoc: Document,
     return queryDoc;
   }
   checkDocument(queryDoc);
+
+  const existingFragmentNames = getFragmentDefinitions(queryDoc)
+    .map((fragment) => fragment.name.value) as String[];
+   const distinctFragments = uniq(fragments.filter((fragment) => {
+     return !includes(existingFragmentNames, fragment.name.value);
+   })) as FragmentDefinition[];
+
   return assign({}, queryDoc, {
-    definitions: queryDoc.definitions.concat(uniq(fragments)),
+    definitions: queryDoc.definitions.concat(distinctFragments),
   }) as Document;
 }

test/getFromAST.ts

@@ -310,6 +310,11 @@ fragment businessAreaInfo on BusinessArea {
           ...businessAreaInfo
         }
       }
+
+      fragment subjectInfo on Subject {
+        id
+        name
+      }
     `;
 
     const fullDoc = addFragmentsToDocument(query, businessAreaInfo);