diff --git a/__tests__/ExpensiMark-Markdown-Truncate-test.js b/__tests__/ExpensiMark-Markdown-Truncate-test.js
new file mode 100644
index 00000000..37bbda4c
--- /dev/null
+++ b/__tests__/ExpensiMark-Markdown-Truncate-test.js
@@ -0,0 +1,108 @@
+import ExpensiMark from '../lib/ExpensiMark';
+
+const parser = new ExpensiMark();
+
+describe('truncateHTML', () => {
+ test('should return original text as HTML if it does not exceed the limit', () => {
+ const markdown = 'This is a *short* text that does not exceed the character limit.';
+ const limit = 100;
+ const html = parser.replace(markdown);
+ const result = parser.truncateHTML(html, limit, {ellipsis: true});
+ expect(result).toBe(html);
+ });
+
+ test('should truncate HTML and add ellipsis if it exceeds the limit', () => {
+ const markdown =
+ 'This is a *long* text that exceeds the character limit. It contains multiple sentences to test the truncation functionality. The truncation should occur at the specified character count.';
+ const limit = 80;
+ const html = parser.replace(markdown);
+ const result = parser.truncateHTML(html, limit, {ellipsis: true});
+ expect(result).toBe('This is a long text that exceeds the character limit. It contains multiple sente...');
+ });
+
+ test('should handle HTML with multiple markdown elements', () => {
+ const markdown =
+ 'This is a *long* text with _multiple_ markdown ~elements~. It includes *bold*, _italic_, and ~strikethrough~ formatting. The truncation should preserve the markdown syntax.';
+ const limit = 150;
+ const html = parser.replace(markdown);
+ const result = parser.truncateHTML(html, limit, {ellipsis: true});
+ expect(result).toBe(
+ 'This is a long text with multiple markdown elements. It includes bold, italic, and strikethrough formatting. The truncation should preserve the markdo...',
+ );
+ });
+
+ test('should handle HTML with nested markdown elements', () => {
+ const markdown = 'This is a *long _nested_ markdown* text. It contains *_bold italic_* and ~_strikethrough italic_~ formatting. The truncation should handle the nesting correctly.';
+ const limit = 120;
+ const html = parser.replace(markdown);
+ const result = parser.truncateHTML(html, limit, {ellipsis: true});
+ expect(result).toBe(
+ 'This is a long nested markdown text. It contains bold italic and strikethrough italic formatting. The truncation should ...',
+ );
+ });
+
+ test('should handle HTML with links', () => {
+ const markdown =
+ 'This is a text with [a link](https://example.com) that exceeds the limit. The link should be preserved in the truncated text. Additionally, it includes [another link](https://example.org) for testing purposes.';
+ const limit = 141;
+ const html = parser.replace(markdown);
+ const result = parser.truncateHTML(html, limit, {ellipsis: true});
+ expect(result).toBe(
+ `This is a text with a link that exceeds the limit. The link should be preserved in the truncated text. Additionally, it includes another link...`,
+ );
+ });
+
+ test('should handle HTML with inline code', () => {
+ const markdown = 'This is a text with `inline code`. The inline code should be preserved in the truncated text.';
+ const limit = 25;
+ const html = parser.replace(markdown);
+ const result = parser.truncateHTML(html, limit, {ellipsis: true});
+ expect(result).toBe('This is a text with inlin...
');
+ });
+
+ test('should handle HTML with headings', () => {
+ const markdown =
+ '# Heading 1\n\nThis is a text with headings that exceeds the limit. The headings should be preserved in the truncated text. Here is an example of a heading:\n\n## Heading 2\n\nThe truncation should handle headings correctly.';
+ const limit = 100;
+ const html = parser.replace(markdown);
+ const result = parser.truncateHTML(html, limit, {ellipsis: true});
+ expect(result).toBe('
Heading 1
This is a text with headings that exceeds the limit. The headings should be preserved in th...');
+ });
+
+ test('should handle HTML with lists', () => {
+ const markdown = `
+ This is a text with lists. Here are examples:
+
+ Unordered list:
+ - Item 1
+ - Item 2
+ - Item 3
+
+ Ordered list:
+ 1. First item
+ 2. Second item
+ 3. Third item
+ `;
+ const limit = 250; // Increased to accommodate full lists
+ const html = parser.replace(markdown);
+ const result = parser.truncateHTML(html, limit, {ellipsis: false});
+ expect(result).toBe(`
This is a text with lists. Here are examples:
Unordered list:
- Item 1
- Item 2
- Item 3
Ordered list:
1. First item
2. Second item
3. Third item
`);
+ });
+
+ test('should handle HTML with horizontal rules', () => {
+ const markdown = 'This is a text with horizontal rules. Here is an example of a horizontal rule:\n\n---\n\nThe truncation should handle horizontal rules correctly.';
+ const limit = 100;
+ const html = parser.replace(markdown);
+ const result = parser.truncateHTML(html, limit, {ellipsis: true});
+ expect(result).toBe('This is a text with horizontal rules. Here is an example of a horizontal rule:
---
The truncation shou...');
+ });
+
+ test('should handle HTML with images', () => {
+ const markdown =
+ 'This is a text with an image ![alt text](https://example.com/image.jpg) that exceeds the limit. The image should be preserved in the truncated text. Additionally, it includes another image ![alt text 2](https://example.org/image2.jpg) for testing purposes.';
+ const limit = 80;
+ const html = parser.replace(markdown);
+ const result = parser.truncateHTML(html, limit, {ellipsis: true});
+ expect(result).toBe('This is a text with an image that exceeds the limit. The image should be preser...');
+ });
+});
diff --git a/lib/ExpensiMark.ts b/lib/ExpensiMark.ts
index 311974cb..dd04a638 100644
--- a/lib/ExpensiMark.ts
+++ b/lib/ExpensiMark.ts
@@ -42,6 +42,13 @@ type ReplaceOptions = {
shouldKeepRawInput?: boolean;
};
+type TruncateOptions = {
+ ellipsis?: string;
+ truncateLastWord?: boolean;
+ slop?: number;
+ removeImageTag?: boolean;
+};
+
const MARKDOWN_LINK_REGEX = new RegExp(`\\[([^\\][]*(?:\\[[^\\][]*][^\\][]*)*)]\\(${UrlPatterns.MARKDOWN_URL_REGEX}\\)(?![^<]*(<\\/pre>|<\\/code>))`, 'gi');
const MARKDOWN_IMAGE_REGEX = new RegExp(`\\!(?:\\[([^\\][]*(?:\\[[^\\][]*][^\\][]*)*)])?\\(${UrlPatterns.MARKDOWN_URL_REGEX}\\)(?![^<]*(<\\/pre>|<\\/code>))`, 'gi');
@@ -1233,6 +1240,198 @@ export default class ExpensiMark {
return Utils.escape(originalContent);
}
+ /**
+ * Determines the end position to truncate the HTML content while considering word boundaries.
+ *
+ * @param {string} content - The HTML content to be truncated.
+ * @param {number} tailPosition - The position up to which the content should be considered.
+ * @param {number} maxLength - The maximum length of the truncated content.
+ * @param {number} totalLength - The length of the content processed so far.
+ * @param {Object} opts - Options to customize the truncation.
+ * @returns {number} The calculated position to truncate the content.
+ */
+ getEndPosition(content: string, tailPosition: number | undefined, maxLength: number, totalLength: number, opts: TruncateOptions) {
+ const WORD_BREAK_REGEX = /\W+/g;
+
+ // Calculate the default position to truncate based on the maximum length and the length of the content processed so far
+ const defaultPosition = maxLength - totalLength;
+
+ // Define the slop value, which determines the tolerance for cutting off content near the maximum length
+ const slop = opts.slop;
+ if (!slop) return defaultPosition;
+
+ // Initialize the position to the default position
+ let position = defaultPosition;
+
+ // Determine if the default position is considered "short" based on the slop value
+ const isShort = defaultPosition < slop;
+
+ // Calculate the position within the slop range
+ const slopPos = isShort ? defaultPosition : slop - 1;
+
+ // Extract the substring to analyze for word boundaries, considering the slop and tail position
+ const substr = content.slice(isShort ? 0 : defaultPosition - slop, tailPosition !== undefined ? tailPosition : defaultPosition + slop);
+
+ // Find the first word boundary within the substring
+ const wordBreakMatch = WORD_BREAK_REGEX.exec(substr);
+
+ // Adjust the position to avoid truncating in the middle of a word if the option is enabled
+ if (!opts.truncateLastWord) {
+ if (tailPosition && substr.length <= tailPosition) {
+ // If tail position is defined and the substring length is within the tail position, set position to the substring length
+ position = substr.length;
+ } else {
+ // Iterate through word boundary matches to adjust the position
+ while (wordBreakMatch !== null) {
+ if (wordBreakMatch.index < slopPos) {
+ // If the word boundary is before the slop position, adjust position backward
+ position = defaultPosition - (slopPos - wordBreakMatch.index);
+ if (wordBreakMatch.index === 0 && defaultPosition <= 1) {
+ break;
+ }
+ } else if (wordBreakMatch.index === slopPos) {
+ // If the word boundary is at the slop position, set position to the default position
+ position = defaultPosition;
+ break;
+ } else {
+ // If the word boundary is after the slop position, adjust position forward
+ position = defaultPosition + (wordBreakMatch.index - slopPos);
+ break;
+ }
+ }
+ }
+ // If the character at the determined position is a whitespace, adjust position backward
+ if (content.charAt(position - 1).match(/\s$/)) {
+ position--;
+ }
+ }
+
+ // Return the calculated position to truncate the content
+ return position;
+ }
+
+ /**
+ * Truncate HTML string and keep tag safe.
+ * pulled from https://github.com/huang47/nodejs-html-truncate/blob/master/lib/truncate.js
+ *
+ * @param {string} html - The string that needs to be truncated
+ * @param {number} maxLength - Length of truncated string
+ * @param {Object} [options] - Optional configuration options
+ * @returns {string} The truncated string
+ */
+ truncateHTML(html: string, maxLength: number, options?: TruncateOptions) {
+ const EMPTY_STRING = '';
+ const DEFAULT_TRUNCATE_SYMBOL = '...';
+ const DEFAULT_SLOP = Math.min(10, maxLength);
+ const tagsStack = [];
+ const KEY_VALUE_REGEX = '((?:\\s+(?:\\w+|-)+(?:\\s*=\\s*(?:"(?:\\\\.|[^"\\\\])*"|\'(?:\\\\.|[^\'\\\\])*\'|[^\'">\\s]+))?)*)';
+ const IS_CLOSE_REGEX = '\\s*\\/?\\s*';
+ const CLOSE_REGEX = '\\s*\\/\\s*';
+ const SELF_CLOSE_REGEX = new RegExp(`<\\/?(\\w+)${KEY_VALUE_REGEX}${CLOSE_REGEX}>`);
+ const HTML_TAG_REGEX = new RegExp(`<\\/?(\\w+)${KEY_VALUE_REGEX}${IS_CLOSE_REGEX}>`);
+ const URL_REGEX = /(((ftp|https?):\/\/)[\\-\w@:%_\\+.~#?,&\\/\\/=]+)|((mailto:)?[_.\w\\-]+@([\w][\w\\-]+\.)+[a-zA-Z]{2,3})/g;
+ const IMAGE_TAG_REGEX = new RegExp(``);
+ let truncatedContent = EMPTY_STRING;
+ let totalLength = 0;
+ let matches = HTML_TAG_REGEX.exec(html);
+ let endResult;
+ let index;
+ let tag;
+ let selfClose = null;
+ let htmlString = html;
+
+ const opts = {
+ ellipsis: DEFAULT_TRUNCATE_SYMBOL,
+ truncateLastWord: true,
+ slop: DEFAULT_SLOP,
+ ...options,
+ };
+
+ function removeImageTag(content: string): string {
+ const match = IMAGE_TAG_REGEX.exec(content);
+ if (!match) {
+ return content;
+ }
+
+ const matchIndex = match.index;
+ const matchLength = match[0].length;
+
+ return content.substring(0, matchIndex) + content.substring(matchIndex + matchLength);
+ }
+
+ function closeTags(tags: string[]): string {
+ return tags
+ .reverse()
+ .map((mappedTag) => {
+ return `${mappedTag}>`;
+ })
+ .join('');
+ }
+
+ while (matches) {
+ matches = HTML_TAG_REGEX.exec(htmlString);
+
+ if (!matches) {
+ if (totalLength >= maxLength) {
+ break;
+ }
+
+ matches = URL_REGEX.exec(htmlString);
+ if (!matches || matches.index >= maxLength) {
+ truncatedContent += htmlString.substring(0, this.getEndPosition(htmlString, undefined, maxLength, totalLength, opts));
+ break;
+ }
+
+ while (matches) {
+ endResult = matches[0];
+ if (endResult !== null) {
+ index = matches.index;
+ truncatedContent += htmlString.substring(0, index + endResult.length - totalLength);
+ htmlString = htmlString.substring(index + endResult.length);
+ matches = URL_REGEX.exec(htmlString);
+ }
+ }
+ break;
+ }
+
+ endResult = matches[0];
+ index = matches.index;
+
+ if (totalLength + index > maxLength) {
+ truncatedContent += htmlString.substring(0, this.getEndPosition(htmlString, index, maxLength, totalLength, opts));
+ break;
+ } else {
+ totalLength += index;
+ truncatedContent += htmlString.substring(0, index);
+ }
+
+ if (endResult[1] === '/') {
+ tagsStack.pop();
+ selfClose = null;
+ } else {
+ selfClose = SELF_CLOSE_REGEX.exec(endResult);
+ if (!selfClose) {
+ tag = matches[1];
+ tagsStack.push(tag);
+ }
+ }
+
+ truncatedContent += selfClose ? selfClose[0] : endResult;
+ htmlString = htmlString.substring(index + endResult.length); // Update htmlString
+ }
+
+ if (htmlString.length > maxLength - totalLength && opts.ellipsis) {
+ truncatedContent += opts.ellipsis ? '...' : '';
+ }
+ truncatedContent += closeTags(tagsStack);
+
+ if (opts.removeImageTag) {
+ truncatedContent = removeImageTag(truncatedContent);
+ }
+
+ return truncatedContent;
+ }
+
/**
* Replaces text with a replacement based on a regex
* @param text - The text to replace