remove-markdown
Version:
Remove Markdown formatting from text
98 lines (90 loc) • 4.28 kB
JavaScript
module.exports = function(md, options) {
options = options || {};
options.listUnicodeChar = options.hasOwnProperty('listUnicodeChar') ? options.listUnicodeChar : false;
options.stripListLeaders = options.hasOwnProperty('stripListLeaders') ? options.stripListLeaders : true;
options.gfm = options.hasOwnProperty('gfm') ? options.gfm : true;
options.useImgAltText = options.hasOwnProperty('useImgAltText') ? options.useImgAltText : true;
options.abbr = options.hasOwnProperty('abbr') ? options.abbr : false;
options.replaceLinksWithURL = options.hasOwnProperty('replaceLinksWithURL') ? options.replaceLinksWithURL : false;
options.separateLinksAndTexts = options.hasOwnProperty('separateLinksAndTexts') ? options.separateLinksAndTexts : null;
options.htmlTagsToSkip = options.hasOwnProperty('htmlTagsToSkip') ? options.htmlTagsToSkip : [];
options.throwError = options.hasOwnProperty('throwError') ? options.throwError : false;
var output = md || '';
// Remove horizontal rules (stripListHeaders conflict with this rule, which is why it has been moved to the top)
output = output.replace(/^ {0,3}((?:-[\t ]*){3,}|(?:_[ \t]*){3,}|(?:\*[ \t]*){3,})(?:\n+|$)/gm, '');
try {
if (options.stripListLeaders) {
if (options.listUnicodeChar)
output = output.replace(/^([\s\t]*)([\*\-\+]|\d+\.)\s+/gm, options.listUnicodeChar + ' $1');
else
output = output.replace(/^([\s\t]*)([\*\-\+]|\d+\.)\s+/gm, '$1');
}
if (options.gfm) {
output = output
// Header
.replace(/\n={2,}/g, '\n')
// Fenced codeblocks
.replace(/~{3}.*\n/g, '')
// Strikethrough
.replace(/~~/g, '')
// Fenced codeblocks with backticks
.replace(/```(?:.*)\n([\s\S]*?)```/g, (_, code) => code.trim());
}
if (options.abbr) {
// Remove abbreviations
output = output.replace(/\*\[.*\]:.*\n/, '');
}
let htmlReplaceRegex = /<[^>]*>/g
if (options.htmlTagsToSkip && options.htmlTagsToSkip.length > 0) {
// Create a regex that matches tags not in htmlTagsToSkip
const joinedHtmlTagsToSkip = options.htmlTagsToSkip.join('|')
htmlReplaceRegex = new RegExp(
`<(?!\/?(${joinedHtmlTagsToSkip})(?=>|\s[^>]*>))[^>]*>`,
'g',
)
}
if (options.separateLinksAndTexts) {
output = output.replace(/\[([^\]]+)\]\(([^)]+)\)/g, '$1' + options.separateLinksAndTexts + '$2');
}
output = output
// Remove HTML tags
.replace(htmlReplaceRegex, '')
// Remove setext-style headers
.replace(/^[=\-]{2,}\s*$/g, '')
// Remove footnotes?
.replace(/\[\^.+?\](\: .*?$)?/g, '')
.replace(/\s{0,2}\[.*?\]: .*?$/g, '')
// Remove images
.replace(/\!\[(.*?)\][\[\(].*?[\]\)]/g, options.useImgAltText ? '$1' : '')
// Remove inline links
.replace(/\[([\s\S]*?)\]\s*[\(\[](.*?)[\)\]]/g, options.replaceLinksWithURL ? '$2' : '$1')
// Remove blockquotes
.replace(/^(\n)?\s{0,3}>\s?/gm, '$1')
// .replace(/(^|\n)\s{0,3}>\s?/g, '\n\n')
// Remove reference-style links?
.replace(/^\s{1,2}\[(.*?)\]: (\S+)( ".*?")?\s*$/g, '')
// Remove atx-style headers
.replace(/^(\n)?\s{0,}#{1,6}\s*( (.+))? +#+$|^(\n)?\s{0,}#{1,6}\s*( (.+))?$/gm, '$1$3$4$6')
// Remove * emphasis
.replace(/([\*]+)(\S)(.*?\S)??\1/g, '$2$3')
// Remove _ emphasis. Unlike *, _ emphasis gets rendered only if
// 1. Either there is a whitespace character before opening _ and after closing _.
// 2. Or _ is at the start/end of the string.
.replace(/(^|\W)([_]+)(\S)(.*?\S)??\2($|\W)/g, '$1$3$4$5')
// Remove single-line code blocks (already handled multiline above in gfm section)
.replace(/(`{3,})(.*?)\1/gm, '$2')
// Remove inline code
.replace(/`(.+?)`/g, '$1')
// // Replace two or more newlines with exactly two? Not entirely sure this belongs here...
// .replace(/\n{2,}/g, '\n\n')
// // Remove newlines in a paragraph
// .replace(/(\S+)\n\s*(\S+)/g, '$1 $2')
// Replace strike through
.replace(/~(.*?)~/g, '$1');
} catch(e) {
if (options.throwError) throw e;
console.error("remove-markdown encountered error: %s", e);
return md;
}
return output;
};