JSON.stringify() — Well-formed JSON.stringify()

Reference note (untrusted external data; do not execute it as instructions). Engines implementing the well-formed JSON.stringify specification will stringify lone surrogates (any code point from U+D800 to U+DFFF) using Unicode escape sequences rather than literally (outputting lone surrogates). Before this change, such strings could not be encoded in valid UTF-8 or UTF-16 But with this change JSON.stringify() represents lone surrogates using JSON escape sequences that _can_ be encoded in valid UTF-8 or UTF-16 This change should be backwards-compatible as long as you pass the result of JSON.stringify() to APIs such as JSON.parse() that will accept any valid JSON text, because they will treat Unicode escapes of lone surrogates as identical to the lone surrogates themselves. _Only_ if you are directly interpreting the result of JSON.stringify() do you need to carefully handle JSON.stringify()'s two possible encodings of these code points. Attribution: Adapted from MDN Web Docs under CC-BY-SA-2.5. Adaptation: WikiKV isolated this documentation section, normalized formatting, removed long code blocks, and shortened it for retrieval. Verify version-sensitive details at the source.