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