remove-markdown/test/remove-markdown.js

Remove Markdown formatting from text

'use strict';
const expect = require('chai').expect;
const removeMd = require('../');

describe('remove Markdown', function () {
  describe('removeMd', function () {
    it('should leave a string alone without markdown', function () {
      const string = 'Javascript Developers are the best.';
      expect(removeMd(string)).to.equal(string);
    });

    it('should strip out remaining markdown', function () {
      const string = '*Javascript* developers are the _best_.';
      const expected = 'Javascript developers are the best.';
      expect(removeMd(string)).to.equal(expected);
    });

    it('should leave non-matching markdown markdown', function () {
      const string = '*Javascript* developers* are the _best_.';
      const expected = 'Javascript developers* are the best.';
      expect(removeMd(string)).to.equal(expected);
    });

    it('should leave non-matching markdown, but strip empty anchors', function () {
      const string = '*Javascript* [developers]()* are the _best_.';
      const expected = 'Javascript developers* are the best.';
      expect(removeMd(string)).to.equal(expected);
    });

    it('should strip HTML', function () {
      const string = '<p>Hello World</p>';
      const expected = 'Hello World';
      expect(removeMd(string)).to.equal(expected);
    });

    it('should strip anchors', function () {
      const string = '*Javascript* [developers](https://engineering.condenast.io/)* are the _best_.';
      const expected = 'Javascript developers* are the best.';
      expect(removeMd(string)).to.equal(expected);
    });

    it('should strip img tags', function () {
      const string = '![](https://placebear.com/640/480)*Javascript* developers are the _best_.';
      const expected = 'Javascript developers are the best.';
      expect(removeMd(string)).to.equal(expected);
    });

    it('should use the alt-text of an image, if it is provided', function () {
      const string = '![This is the alt-text](https://www.example.com/images/logo.png)';
      const expected = 'This is the alt-text';
      expect(removeMd(string)).to.equal(expected);
    });

    it('should strip code tags', function () {
      const string = 'In `Getting Started` we set up `something` foo.';
      const expected = 'In Getting Started we set up something foo.';
      expect(removeMd(string)).to.equal(expected);
    });

    it('should leave hashtags in headings', function () {
      const string = '## This #heading contains #hashtags';
      const expected = 'This #heading contains #hashtags';
      expect(removeMd(string)).to.equal(expected);
    });

    it('should remove emphasis', function () {
      const string = 'I italicized an *I* and it _made_ me *sad*.';
      const expected = 'I italicized an I and it made me sad.';
      expect(removeMd(string)).to.equal(expected);
    });

    it('should remove emphasis only if there is no space between word and emphasis characters.', function () {
      const string = 'There should be no _space_, *before* *closing * _ephasis character _.';
      const expected = 'There should be no space, before *closing * _ephasis character _.';
      expect(removeMd(string)).to.equal(expected);
    });

    it('should remove "_" emphasis only if there is space before opening and after closing emphasis characters.', function () {
      const string = '._Spaces_ _ before_ and _after _ emphasised character results in no emphasis.';
      const expected = '.Spaces _ before_ and _after _ emphasised character results in no emphasis.';
      expect(removeMd(string)).to.equal(expected);
    });

    it('should remove double emphasis', function () {
      const string = '**this sentence has __double styling__**';
      const expected = 'this sentence has double styling';
      expect(removeMd(string)).to.equal(expected);
    });

    it('should not mistake a horizontal rule when symbols are mixed ', function () {
      const string = 'Some text on a line\n\n--*\n\nA line below';
      const expected = 'Some text on a line\n\n--*\n\nA line below';
      expect(removeMd(string)).to.equal(expected);
    });

    it('should remove horizontal rules', function () {
      const string = 'Some text on a line\n\n---\n\nA line below';
      const expected = 'Some text on a line\n\nA line below';
      expect(removeMd(string)).to.equal(expected);
    });

    it('should remove horizontal rules with space-separated asterisks', function () {
      const string = 'Some text on a line\n\n* * *\n\nA line below';
      const expected = 'Some text on a line\n\nA line below';
      expect(removeMd(string)).to.equal(expected);
    });

    it('should remove blockquotes', function () {
      const string = '>I am a blockquote';
      const expected = 'I am a blockquote';
      expect(removeMd(string)).to.equal(expected);
    });

    it('should remove blockquotes with spaces', function () {
      const string = '> I am a blockquote';
      const expected = 'I am a blockquote';
      expect(removeMd(string)).to.equal(expected);
    });

    it('should remove indented blockquotes', function () {
        var tests = [
            { string: ' > I am a blockquote', expected: 'I am a blockquote' },
            { string: '  > I am a blockquote', expected: 'I am a blockquote' },
            { string: '   > I am a blockquote', expected: 'I am a blockquote' },
        ];
        tests.forEach(function (test) {
            expect(removeMd(test.string)).to.equal(test.expected);
        });
    });
    
    it('should remove blockquotes over multiple lines', function () {
      const string = '> I am a blockquote firstline  \n>I am a blockquote secondline';
      const expected = 'I am a blockquote firstline  \nI am a blockquote secondline';
      expect(removeMd(string)).to.equal(expected);
    });

    it('should remove blockquotes following other content', function () {
      const string = '## A headline\n\nA paragraph of text\n\n> I am a blockquote';
      const expected = 'A headline\n\nA paragraph of text\n\nI am a blockquote';

      expect(removeMd(string)).to.equal(expected);
    });

    it('should not remove greater than signs', function () {
      var tests = [
        { string: '100 > 0', expected: '100 > 0' },
        { string: '100 >= 0', expected: '100 >= 0' },
        { string: '100>0', expected: '100>0' },
        { string: '> 100 > 0', expected: '100 > 0' },
        { string: '1 < 100', expected: '1 < 100' },
        { string: '1 <= 100', expected: '1 <= 100' },
      ];
      tests.forEach(function (test) {
        expect(removeMd(test.string)).to.equal(test.expected);
      });
    });

    it('should strip unordered list leaders', function () {
      const string = 'Some text on a line\n\n* A list Item\n* Another list item';
      const expected = 'Some text on a line\n\nA list Item\nAnother list item';
      expect(removeMd(string)).to.equal(expected);
    });

    it('should strip ordered list leaders', function () {
      const string = 'Some text on a line\n\n9. A list Item\n10. Another list item';
      const expected = 'Some text on a line\n\nA list Item\nAnother list item';
      expect(removeMd(string)).to.equal(expected);
    });

    it('should strip list items with bold word in the beginning', function () {
      const string = 'Some text on a line\n\n- **A** list Item\n- **Another** list item';
      const expected = 'Some text on a line\n\nA list Item\nAnother list item';
      expect(removeMd(string)).to.equal(expected);
    });

    it('should handle paragraphs with markdown', function () {
      const paragraph = '\n## This is a heading ##\n\nThis is a paragraph with [a link](http://www.disney.com/).\n\n### This is another heading\n\nIn `Getting Started` we set up `something` foo.\n\n  * Some list\n  * With items\n    * Even indented';
      const expected = '\nThis is a heading\n\nThis is a paragraph with a link.\n\nThis is another heading\n\nIn Getting Started we set up something foo.\n\n  Some list\n  With items\n    Even indented';
      expect(removeMd(paragraph)).to.equal(expected);
    });

    it('should not strip paragraphs without content', function() {
      const paragraph = '\n#This paragraph\n##This paragraph#';
      const expected = paragraph;
      expect(removeMd(paragraph)).to.equal(expected);
    });

    it('should not trigger ReDoS with atx-headers', function () {
      const start = Date.now();

      const paragraph = '\n## This is a long "'+' '.repeat(200)+'" heading ##\n';
      const expected = /\nThis is a long " {200}" heading\n/;
      expect(removeMd(paragraph)).to.match(expected);

      const duration = Date.now()-start;
      expect(duration).to.be.lt(1000);
    });

    it('should work fast even with lots of whitespace', function () {
      const string = 'Some text with lots of                                                                                                                                                                                                       whitespace';
      const expected = 'Some text with lots of                                                                                                                                                                                                       whitespace';
      expect(removeMd(string)).to.equal(expected);
    });

    it('should still remove escaped markdown syntax', function () {
      const string = '\# Heading in _italic_';
      const expected = 'Heading in italic';
      expect(removeMd(string)).to.equal(expected);
    });

    it('should skip specified HTML tags when htmlTagsToSkip option is provided', () => {
      const markdown =
        '<div>HTML content <sub>Superscript</sub> <span>span text</span></div>'
      const result = removeMd(markdown, {htmlTagsToSkip: ['sub']})
      expect(result).to.equal('HTML content <sub>Superscript</sub> span text')
      const result2 = removeMd(markdown, {htmlTagsToSkip: ['sub', 'span']})
      expect(result2).to.equal(
        'HTML content <sub>Superscript</sub> <span>span text</span>',
      )
    })
  });
});