Add ast toString returning query string

Author: darren128

src/index.js

@@ -24,6 +24,12 @@ function resetCaches() {
   fragmentSourceMap = {};
 }
 
+// For defining doc.toString
+function toString(loc) {
+  return loc.source.body;
+
+}
+
 // Take a unstripped parsed document (query/mutation or even fragment), and
 // check all fragment definitions, checking for name->source uniqueness.
 // We also want to make sure only unique fragments exist in the document.
@@ -135,6 +141,7 @@ function parseDocument(doc) {
   // existing fragments of the same name
   parsed = processFragments(parsed);
   parsed = stripLoc(parsed, false);
+  parsed.toString = toString.bind(null, parsed.loc);
   docCache[cacheKey] = parsed;
 
   return parsed;

test/graphql.js

@@ -438,6 +438,13 @@ const assert = require('chai').assert;
       });
     });
 
+    it('returned document toString returns query string', () => {
+      const query = `{ user(id: 5) { firstName lastName } }`;
+      const doc = gql(query);
+
+      assert.equal(doc.toString(), query);
+    });
+
     // How to make this work?
     // it.only('can reference a fragment passed as a document via shorthand', () => {
     //   const ast = gql`