1 files changed, 13 insertions, 0 deletions
diff --git a/src/mongo/gotools/common/json/undefined.go b/src/mongo/gotools/common/json/undefined.go
new file mode 100644
index 00000000000..20cb3e9a8b3
--- /dev/null
+++ b/src/mongo/gotools/common/json/undefined.go
@@ -0,0 +1,13 @@
+package json
+
+// Transition functions for recognizing undefined.
+// Adapted from encoding/json/scanner.go.
+
+// stateU is the state after reading `u`.
+func stateU(s *scanner, c int) int {
+	if c == 'n' {
+		s.step = generateState("undefined", []byte("defined"), stateEndValue)
+		return scanContinue
+	}
+	return s.error(c, "in literal undefined (expecting 'n')")
+}