hardlounge/client/js/helpers/ircmessageparser/findChannels.js

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"use strict";
// Escapes the RegExp special characters "^", "$", "", ".", "*", "+", "?", "(",
// ")", "[", "]", "{", "}", and "|" in string.
// See https://lodash.com/docs/#escapeRegExp
const escapeRegExp = require("lodash/escapeRegExp");
// Given an array of channel prefixes (such as "#" and "&") and an array of user
// modes (such as "@" and "+"), this function extracts channels and nicks from a
// text.
// It returns an array of objects for each channel found with their start index,
// end index and channel name.
function findChannels(text, channelPrefixes, userModes) {
// `userModePattern` is necessary to ignore user modes in /whois responses.
// For example, a voiced user in #thelounge will have a /whois response of:
// > foo is on the following channels: +#thelounge
// We need to explicitly ignore user modes to parse such channels correctly.
const userModePattern = userModes.map(escapeRegExp).join("");
const channelPrefixPattern = channelPrefixes.map(escapeRegExp).join("");
const channelPattern = `(?:^|\\s)[${userModePattern}]*([${channelPrefixPattern}][^ \u0007]+)`;
const channelRegExp = new RegExp(channelPattern, "g");
const result = [];
let match;
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;
}
module.exports = findChannels;