Function DecodeJSStringRune

internal/stringutil/util.go:343–351

(s string)

}

func DecodeJSStringRune(s string) (rune, int) {
	if len(s) >= 3 &&
		s[0] == surrogateUTF8Lead &&
		s[1] >= surrogateUTF8Byte1Min && s[1] <= surrogateUTF8Byte1Max &&
		s[2] >= utf8ContMarker && s[2] <= utf8ContMax {
		return surrogateUTF8LeadBits | rune(s[1]&utf8ContMask)<<6 | rune(s[2]&utf8ContMask), 3
	}
	return utf8.DecodeRuneInString(s)
}

// CombineSurrogatePairs canonicalizes a JS-string value produced by
// concatenation, merging any adjacent high+low surrogate sentinel pair (as