In my opinion in std::wstring JSONValue::StringifyString(const std::wstring &str)
Line 879:
if (chr == L'"' || chr == L'\' || chr == L'/')
should be just:
if (chr == L'"' || chr == L'\')
I found in https://www.ecma-international.org/publications/files/ECMA-ST/Ecma-262.pdf in section 24.5.2 "JSON.stringify" NOTE 3 no special rule for "/".
The link in the comment above the JSONValue::StringifyString function is outdated and the referenced section "Section 15.12.3." does not exists in my document.