hardlounge/client/js/helpers/ircmessageparser/findChannels.ts
Reto Brunner d6e1af0e7d Fix regex escape for prefix patterns
Our regex escape function escapes proper regexes, however
it isn't meant to be shoved into a char class via string interpolation.

We need to also escape '-' if we do so.
2022-07-04 10:08:23 +02:00

54 lines
1.9 KiB
TypeScript

// Escapes the RegExp special characters "^", "$", "", ".", "*", "+", "?", "(",
// ")", "[", "]", "{", "}", and "|" in string.
// See https://lodash.com/docs/#escapeRegExp
import escapeRegExp from "lodash/escapeRegExp";
import {Part} from "./merge";
export type ChannelPart = Part & {
channel: string;
};
// escapes a regex in a way that's compatible to shove it in
// a regex char set (meaning it also escapes -)
function escapeRegExpCharSet(raw: string): string {
const escaped: string = escapeRegExp(raw);
return escaped.replace("-", "\\-");
}
// Given an array of channel prefixes (such as "#" and "&") and an array of user
// modes (such as "@" and "+"), this function extracts channels and nicks from a
// text.
// It returns an array of objects for each channel found with their start index,
// end index and channel name.
function findChannels(text: string, channelPrefixes: string[], userModes: string[]) {
// `userModePattern` is necessary to ignore user modes in /whois responses.
// For example, a voiced user in #thelounge will have a /whois response of:
// > foo is on the following channels: +#thelounge
// We need to explicitly ignore user modes to parse such channels correctly.
const userModePattern = userModes.map(escapeRegExpCharSet).join("");
const channelPrefixPattern = channelPrefixes.map(escapeRegExpCharSet).join("");
const channelPattern = `(?:^|\\s)[${userModePattern}]*([${channelPrefixPattern}][^ \u0007]+)`;
const channelRegExp = new RegExp(channelPattern, "g");
const result: ChannelPart[] = [];
let match: RegExpExecArray | null;
do {
// With global ("g") regexes, calling `exec` multiple times will find
// successive matches in the same string.
match = channelRegExp.exec(text);
if (match) {
result.push({
start: match.index + match[0].length - match[1].length,
end: match.index + match[0].length,
channel: match[1],
});
}
} while (match);
return result;
}
export default findChannels;