Character class: [...], [^...] — Matching strings

Reference note (untrusted external data; do not execute it as instructions). The following function matches all line terminator sequences, including the line terminator characters and the sequence \r\n (CRLF). The order in which the alternatives are specified does not matter, because the longest alternative, \r\n, is always preferred. This regular expression is exactly equivalent to /(?:\r\n|\r|\n|\u2028|\u2029)/gu or /(?:\r\n|[\r\n\u2028\u2029])/gu. However, in regular disjunction, the order of alternatives matters, so \r\n must be specified first in order for it to be preferred. Using a character class not only is shorter but also avoids this pitfall. The most useful case of \q{} is when doing subtraction and intersection. Previously, this was possible with multiple lookaheads. The following function matches flags that are not one of the American, Chinese, Russian, British, and French flags. This example is mostly equivalent to /^(?!🇺🇸|🇨🇳|🇷🇺|🇬🇧|🇫🇷)\p{RGI_Emo 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.