Merge pull request #587 from pkosiec/fix-json-string-arg

Fix quotation during printing StringValue node

language/printer/printer.go

@@ -2,6 +2,7 @@ package printer
 
 import (
 	"fmt"
+	"strconv"
 	"strings"
 
 	"reflect"
@@ -372,7 +373,7 @@ var printDocASTReducer = map[string]visitor.VisitFunc{
 	"StringValue": func(p visitor.VisitFuncParams) (string, interface{}) {
 		switch node := p.Node.(type) {
 		case *ast.StringValue:
-			return visitor.ActionUpdate, `"` + fmt.Sprintf("%v", node.Value) + `"`
+			return visitor.ActionUpdate, strconv.Quote(node.Value)
 		case map[string]interface{}:
 			return visitor.ActionUpdate, `"` + getMapValueString(node, "Value") + `"`
 		}

language/printer/printer_test.go

@@ -186,3 +186,17 @@ fragment frag on Follower {
 		t.Fatalf("Unexpected result, Diff: %v", testutil.Diff(expected, results))
 	}
 }
+
+func TestPrinter_CorrectlyPrintsStringArgumentsWithProperQuoting(t *testing.T) {
+	queryAst := `query { foo(jsonStr: "{\"foo\": \"bar\"}") }`
+	expected := `{
+  foo(jsonStr: "{\"foo\": \"bar\"}")
+}
+`
+	astDoc := parse(t, queryAst)
+	results := printer.Print(astDoc)
+
+	if !reflect.DeepEqual(expected, results) {
+		t.Fatalf("Unexpected result, Diff: %v", testutil.Diff(expected, results))
+	}
+}