JavaScript Hook for Composer

I had a previous post that did not get any response, maybe because the request was too narrow. So here I try again: I would like to hook into the compose editor so that when the user types a certain sequence of characters (e.g. --) followed by a query, I can show a popup with search results. Once the user clicks one of those, a normal link is inserted where the query was typed. What is best practise to access the composer element and have my plugin notified once the user composes a post? I had a look at the plugin API and some plugins on GitHub, but could not find any good example.
Kind regards

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I suspect you want to follow an existing example.

The place to look, I suspect, is discourse/d-editor.js.es6 at f62b8990acb9ce4af8bfc67fc80dc0847177e458 · discourse/discourse · GitHub


  didInsertElement() {

    const $editorInput = $(this.element.querySelector(".d-editor-input"));

And maybe take a look at:

  _applyCategoryHashtagAutocomplete() {
    const siteSettings = this.siteSettings;

      template: findRawTemplate("category-tag-autocomplete"),
      key: "#",
      afterComplete: () => this._focusTextArea(),
      transformComplete: obj => {
        return obj.text;
      dataSource: term => {
        if (term.match(/\s/)) {
          return null;
        return searchCategoryTag(term, siteSettings);
      triggerRule: (textarea, opts) => {
        return categoryHashtagTriggerRule(textarea, opts);

NB I’ve not exploited this myself, but that’s my guess.

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Hi @merefield,
thanks a lot, this is already quite helpful. Just where is the best place to initialize this? Should I check in my plugin’s initializer function whether .d-editor-input element exists and hook it up accordingly, or is there a place to register the plugin as an extension to the compose view, so that it only gets loaded when the user actually opens the composer.
Kind regards

This is a Component, handilly, so you would want to override this method didInsertElement() in your initializer.


withPluginApi('0.8.12', (api) => {


from here discourse-topic-previews/preview-edits.js.es6 at master · paviliondev/discourse-topic-previews · GitHub

If you are lucky you can just call this._super(); and append your additional logic at the end.


Perfect! Thanks a lot. I think this will do the trick.

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