Get ServiceNow Journal Entries, optionally parse and convert HTML control-characters and line-breaks, and return an array of the last N journal entries.

getJournalEntries.js

/**
 * Get the journal entries from a given record, and optionally parse and convert line breaks and
 * HTML and wokkas (< and >) to HTML (<br />\n and HTML-ized character codes).
 * @param {GlideRecord} current - A GlideRecord object positioned to the record you want to get the
 *     journal entries from.
 * @param {String} journalFieldName - The journal field name (e.g. "work_notes", "comments",
 *     "comments_and_work_notes", etc.).
 * @param {Boolean} [convertLineBreaksToHTML=false] - Set this to true, to convert line-breaks
 *     (\r\n) to HTML (<br />\n).
 * @param {Boolean} [convertWokkasToHTML=false] - Set this to true, to convert wokkas ("<" and ">")
 *     to HTML ("&#[char_code];").
 * @param {Number} [getLastNEntries=-1] - Specify the number of journal entries you'd like to
 *     retrieve. If not specified, the default is -1.
 * Set this to -1 (or leave undefined) to retrieve ALL entries from the specified journal field.
 * @param {function} [filterFunction=] - Optionally, specify a function that can be used to filter
 *     the results. This function will be called for each individual journal entry AFTER any other
 *     processing (such as HTML conversion). The function must accept one argument (the individual
 *     journal entry, as a string) and return the boolean value true if the journal entry passed
 *     into it matches your filter.
 *  For example:
 *  function checkJournalEntryContainsString(journalEntry) {
 *      return journalEntry.includes('SOME_STRING') || journalEntry.length < 100;
 * }
 * Passing the above checkJournalEntryContainsString function into getJournalEntries() as the last
 *     argument will cause getJournalEntries() to ONLY include journal entries that contain the
 *     text "SOME_STRING", *or* which are less than 100 characters in length. NOTE: When PASSING a
 *     function into another function as an argument, just pass it in by name. Do NOT include the
 *     "()" after the function name.
 * If you DON'T want to filter the returned results, then simply do not specify this argument.
 * @returns {String[]} - An array of journal entries from the specified journal field on the
 *  specified record, with the specified parsing done.
 *
 * @example
 * var arrWorkNotes;
 * var grInc = new GlideRecord('incident');
 * grInc.setLimit(1);
 * grInc.query();
 * if (grInc.next()) {
 * 	arrWorkNotes = getJournalEntries(
 * 		grInc,
 * 		'work_notes',
 * 		true,
 * 		true,
 * 		2
 * 	);
 * 	gs.info(JSON.stringify(arrWorkNotes, null, 2));
 * }
 * //Output:
 * //['2022-08-16 10:31:11 - Admin (Work notes)\nThis is an example journal entry <br />\n<br    />\nwith a lot of<br />\nextraneous<br />\n<br />\n<br />\nline breaks.', '2022-08-16    10:30:58 - Admin (Work notes)\nThis is an example journal entry with <br />\nline breaks,    and &#60;HTML wokkas that&#62; need to be converted to HTML.'];
 *
 * //Example 2:
 * function myFilterFunction(strJournalEntry) {
 * 	//Filter results: only include entries including this text, or less than 100 chars long
 * 	return (
 * 		strJournalEntry.includes('Some text to check for') ||
 * 		strJournalEntry.length < 100
 * 	);
 * }
 *
 * var arrCommentsAndWorknotes = getJournalEntries(
 * 	current,
 * 	'comments_and_work_notes',
 * 	false,
 * 	false,
 * 	-1, //Get ALL journal entries
 * 	myFilterFunction
 * );
 */
function getJournalEntries(
	current,
	journalFieldName,
	convertLineBreaksToHTML,
	convertWokkasToHTML,
	getLastNEntries,
	filterFunction
) {
	
	//Hoist declarations
	var arrJournalEntries, strJournalEntries;
	
	//Init default values for optional params
	convertLineBreaksToHTML = (typeof convertLineBreaksToHTML == 'undefined') ? false : convertLineBreaksToHTML;
	convertWokkasToHTML = (typeof convertWokkasToHTML == 'undefined') ? false : convertWokkasToHTML;
	getLastNEntries = (typeof getLastNEntries == 'undefined') ? -1 : parseInt(getLastNEntries);
	
	//Get all journal entries from the specified field as an array of strings.
	strJournalEntries = current[journalFieldName] //Chain-call incoming...
		//Arg -1 gets all journal entries in a string, delimited by "\n\n"
		.getJournalEntry(getLastNEntries)
		//Explicitly cast value to string to avoid unexpected type-coercion
		.toString()
		//Trim trailing whitespace (which would otherwise result is a trailing empty element)
		.trim();
	
	if (convertWokkasToHTML) {
		if (strJournalEntries.includes('<') || strJournalEntries.includes('>')) {
			strJournalEntries = strJournalEntries.replaceAll(
				'<',
				('&#' + '<'.charCodeAt(0) + ';')
			);
			
			strJournalEntries = strJournalEntries.replaceAll(
				'>',
				('&#' + '>'.charCodeAt(0) + ';')
			);
		}
	}
	
	if (convertLineBreaksToHTML) {
		//Replace embedded returns in journal entry with HTML break if necessary
		strJournalEntries = strJournalEntries.replaceAll(
			'\r\n', (convertLineBreaksToHTML ? '<br />\n' : '\r\n')
		);
	}
	
	//Split the string on double-new-line-character to get unique journal entries
	arrJournalEntries = strJournalEntries.split('\n\n');
	/*
	NOTE: Splitting on the double-new-line-character may seem risky. What if a user creates
	 a journal entry with a double-return in it, for example? -- However, this is not the
	 case. New-lines inside of journal entries are converted to "\r\n" for each new line.
	
	For example, the following journal entry:
		"This
		
		is a test"
	
	Will be converted to:
		"This\r\n\r\nis a test"
		
	Note that each line-return in the original entry is converted to "\r\n". Therefore, when
	 splitting on "\n\n", we should expect no conflict.
	*/
	
	//Fail early: If no journal entries are found, bail out here.
	if (!arrJournalEntries || arrJournalEntries.length < 1) {
		return []; //No journal entries found. Halt and return, but throw no error or warning.
	}
	
	//If filterFunction arg is provided, filter journal entries using that function.
	if (typeof filterFunction == 'function') {
		arrJournalEntries = arrJournalEntries.filter(filterFunction);
	}
	
	return arrJournalEntries;
	
}