A small struct wrapper around time.Time which correctly maps null
JSON values to the zero time. Additionally it uses the
time.RFC3339Nano format like gqlgen does.

I've considered using pointers but that'd force callers to
explicitly check for nil values instead of handling idiomatic zero
time values.
---
 cmd/gqlclientgen/main.go |  2 +-
 time.go                  | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+), 1 deletion(-)
 create mode 100644 time.go

diff --git a/cmd/gqlclientgen/main.go b/cmd/gqlclientgen/main.go
index b7a68ac0d5c5..a7a0d65dd7b6 100644
--- a/cmd/gqlclientgen/main.go
+++ b/cmd/gqlclientgen/main.go
@@ -79,7 +79,7 @@ func genType(schema *ast.Schema, t *ast.Type) jen.Code {
 		gen = jen.String()
 	// Convenience types
 	case "Time":
-		gen = jen.Qual("time", "Time")
+		gen = jen.Qual(gqlclient, "Time")
 	case "Map":
 		gen = jen.Map(jen.String()).Interface()
 	case "Upload":
diff --git a/time.go b/time.go
new file mode 100644
index 000000000000..a5ab8687ce3d
--- /dev/null
+++ b/time.go
@@ -0,0 +1,36 @@
+package gqlclient
+
+import (
+	"encoding/json"
+	"time"
+)
+
+const timeLayout = time.RFC3339Nano
+
+type Time struct {
+	time.Time
+}
+
+func (t Time) MarshalJSON() ([]byte, error) {
+	var v interface{}
+	if !t.IsZero() {
+		v = t.Format(timeLayout)
+	}
+	return json.Marshal(v)
+}
+
+func (t *Time) UnmarshalJSON(b []byte) error {
+	if string(b) == "null" {
+		t.Time = time.Time{}
+		return nil
+	}
+
+	var s string
+	if err := json.Unmarshal(b, &s); err != nil {
+		return err
+	}
+
+	var err error
+	t.Time, err = time.Parse(timeLayout, s)
+	return err
+}
-- 
2.39.1