SyntaxError: Invalid regular expression: /{/u: Lone quantifier brackets (V8-based)SyntaxError: raw bracket is not allowed in regular expression with unicode flag (Firefox)SyntaxError: Invalid regular expression: incomplete {} quantifier for Unicode pattern (Safari)SyntaxError: Invalid regular expression: unmatched ] or } bracket for Unicode pattern (Safari)

In Unicode-unaware mode,{,}, and] that are not part of a quantifier or character class are treated as literal characters. This may hide errors in your code and is therefore deprecated and disallowed in Unicode-aware mode. You should either check whether you have invalid syntax or you shouldescape the characters to match them literally.

If{ appears in a context that accepts aquantifier, it is treated as the start of a quantifier. If what follows it is not a valid quantifier, another syntax error,incomplete quantifier, is thrown.

• Regular expressions
• Character class:[...],[^...]
• Character escape:\n,\u{...}
• Quantifier:*,+,?,{n},{n,},{n,m}