Hashtag linked categories do not show up properly in the composer

GaurangTandon · March 19, 2016, 4:31am

I got the relevant files after some manual digging. They are these three:

app/assets/javascripts/discourse/dialects/category_hashtag_dialect.js

fb6bd10d4

/**
  Supports Discourse's category hashtags (#category-slug) for automatically
  generating a link to the category.
**/
Discourse.Dialect.inlineRegexp({
  start: '#',
  matcher: /^#([\w-:]{1,101})/i,
  spaceOrTagBoundary: true,

  emitter: function(matches) {
    var slug = matches[1],
        hashtag = matches[0],
        attributeClass = 'hashtag',
        categoryHashtagLookup = this.dialect.options.categoryHashtagLookup,
        result = categoryHashtagLookup && categoryHashtagLookup(slug);

    if (result) {
      return ['a', { class: attributeClass, href: result[0] }, '#', ["span", {}, result[1]]];
    } else {
      return ['span', { class: attributeClass }, hashtag];

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github.com/discourse/discourse

app/assets/javascripts/discourse/lib/category-hashtags.js.es6

350f1685e

export const SEPARATOR = ":";

export function replaceSpan($elem, categorySlug, categoryLink) {
  $elem.replaceWith(`<a href="${categoryLink}" class="hashtag">#<span>${categorySlug}</span></a>`);
};

export function categoryHashtagTriggerRule(textarea, opts) {
  const result = Discourse.Utilities.caretRowCol(textarea);
  const row = result.rowNum;
  var col = result.colNum;
  var line = textarea.value.split("\n")[row - 1];

  if (opts && opts.backSpace) {
    col = col - 1;
    line = line.slice(0, line.length - 1);

    // Don't trigger autocomplete when backspacing into a `#category |` => `#category|`
    if (/^#{1}\w+/.test(line)) return false;
  }

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The following file adds the "hashtag-tested" class:

github.com/discourse/discourse

app/assets/javascripts/discourse/lib/link-category-hashtags.js.es6

c2c1aea38

import { replaceSpan } from 'discourse/lib/category-hashtags';

const validCategoryHashtags = {};
const checkedCategoryHashtags = [];
const testedKey = 'tested';
const testedClass = `hashtag-${testedKey}`;

function updateFound($hashtags, categorySlugs) {
  Ember.run.schedule('afterRender', () => {
    $hashtags.each((index, hashtag) => {
      const categorySlug = categorySlugs[index];
      const link = validCategoryHashtags[categorySlug];
      const $hashtag = $(hashtag);

      if (link) {
        replaceSpan($hashtag, categorySlug, link);
      } else if (checkedCategoryHashtags.indexOf(categorySlug) !== -1) {
        $hashtag.addClass(testedClass);
      }
    });

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Now, it should be probably easy to find the bug.

Topic		Replies	Views
Category dropdown missing in composer Bug lazy-load-categories	1	146	February 3, 2026
Incorrect composer prompt about links being used in a topic Bug	1	132	October 15, 2025
Hashtag linking to categories doesn’t always work Bug	10	3034	March 15, 2016
Category from /new-topic route not displayed in composer Bug	2	864	August 25, 2017
All links to categories broken? Product Support	9	1204	November 2, 2023

Hashtag linked categories do not show up properly in the composer

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