code: public static boolean equal(SoyValue operand0, SoyValue operand1) {
      // Treat the case where either is a string specially.
      // TODO(gboyer): This should probably handle SanitizedContent == SanitizedContent, even though
      // Javascript doesn't handle that case properly. http://b/21461181
      if (operand0 instanceof StringData || operand0 instanceof UnsanitizedString) {
        return compareString(operand0.stringValue(), operand1);
      }
      if (operand1 instanceof StringData || operand1 instanceof UnsanitizedString) {
        return compareString(operand1.stringValue(), operand0);
      }
      return Objects.equals(operand0, operand1);
    }
docs: Custom equality operator that smooths out differences between different Soy runtimes.
  
  <p>This approximates Javascript's behavior, but is much easier to understand.