Leaf

Visual WYSIWYG + Obsidian-style hybrid live preview + markdown editor for Phoenix LiveView.

Live Demo

• Visual mode: contenteditable div with toolbar formatting (bold, italic, headings, lists, links, code blocks, tables, blockquotes, inline spoilers, etc.)
• Hybrid mode (Obsidian-style live preview): formatting renders inline (bold, italic, strike, code, spoiler, headings, horizontal rule, lists) while the source markers stay editable — typing **word**, *word*, ~~word~~, ||word||, `word`, # heading, ---, - item, or 1. item auto-formats on the closing delimiter, and the markers fade in/out as the cursor enters and leaves each formatted run
• Markdown mode: plain textarea with toolbar support
• HTML mode: raw HTML editing for power users
• Responsive toolbar: compact, stationary controls for narrow embeds and mobile comment editors; advanced tools progressively move into menus instead of requiring horizontal scrolling
• Drag-and-drop reordering: drag any block element (headings, paragraphs, lists, images, blockquotes, code blocks) to rearrange content
• Resizable: drag the bottom-right grip to change height; double-click the grip to auto-fit to content
• Spoilers: Discord-style ||hidden|| markdown that renders as a click-to-reveal censored block in published content
• Content syncs between modes via Earmark and client-side HTML→Markdown conversion
• No npm dependencies — vendored JS bundle

Installation

Add leaf to your dependencies in mix.exs:

def deps do
  [
    {:leaf, "~> 0.4.0"}
  ]
end

JavaScript Setup

In your app.js, import the JS and register the hook:

import "../../../deps/leaf/priv/static/assets/leaf.js"

let liveSocket = new LiveSocket("/live", Socket, {
  hooks: {
    Leaf: window.LeafHooks.Leaf,
    // ... your other hooks
  }
})

CDN Alternative

If you prefer not to use the deps/ import path (e.g., non-standard project structure), you can load the JS from CDN instead:

// Load Leaf from CDN
const script = document.createElement("script");
script.src = "https://cdn.jsdelivr.net/gh/alexdont/leaf@v0.4.0/priv/static/assets/leaf.js";
script.onload = () => {
  // Leaf is now available at window.LeafHooks
};
document.head.appendChild(script);

Peer Requirements

Leaf's toolbar uses Tailwind CSS + daisyUI classes (btn, btn-xs, divider, textarea, etc.) and Heroicons CSS classes (hero-*). Make sure these are available in your project.

Usage

First, import the component in your view helpers (e.g., in my_app_web.ex):

import Leaf, only: [leaf_editor: 1]

Then use it in your templates:

<.leaf_editor
  id="my-editor"
  content={@content}
  mode={:visual}
  toolbar={[:image, :video]}
  deny={[:links, :images, :markdown_mode]}
  placeholder="Write something..."
  readonly={false}
  height="480px"
  debounce={400}
/>

<.live_component
  module={Leaf}
  id="my-editor"
  content={@content}
  mode={:visual}
  toolbar={[:image, :video]}
  deny={[:links, :images, :markdown_mode]}
  placeholder="Write something..."
  readonly={false}
  height="480px"
  debounce={400}
/>

Assigns

Inline suggestions

The editor can offer a popup as the writer types a trigger character — # for tags, @ for people, / for components, : for emoji. It knows nothing about any of those: it detects a configured trigger, asks the host what matches, renders the list and inserts the pick. Works in all four modes.

<.leaf_editor
  id="post-editor"
  content={@content}
  suggestions={[
    %{
      trigger: "#",
      boundary: :word_start,
      token: ~r/[\p{L}\p{N}_-]/u,
      first_char: ~r/\p{L}/u,
      max_length: 30,
      allow_create: true,
      insert_suffix: " ",
      label: "Tags"
    }
  ]}
/>

def handle_info({:leaf_suggest, %{editor_id: id, trigger: "#", query: q, seq: seq}}, socket) do
  results =
    Enum.map(my_tag_source(q), fn tag ->
      %{value: tag.name, label: "##{tag.name}", sublabel: "#{tag.count} posts", icon: "hero-hashtag"}
    end)

  send_update(Leaf, id: id, action: :suggestions, trigger: "#", query: q, seq: seq, results: results)
  {:noreply, socket}
end

Every config key but :trigger is optional; keys may be atoms or strings. :boundary (:word_start / :line_start / :any), :token, :first_char, :min_chars, :max_length, :debounce, :max_results, :allow_create, :keep_trigger, :insert_suffix, :label and :exclude are documented in full in the Leaf moduledoc.

Two rules matter more than the shape: echo trigger, query and seq back unchanged so the client can drop replies a later keystroke superseded, and know that typing is never blocked — a host that never answers gets a short spinner and then the popup closes on its own.

By default the popup stays shut inside fenced/inline code, inside a markdown link destination ([jump](#section)) and after a non-space character (URL fragments like /page#section). ↑/↓ move, Enter and Tab accept, Escape dismisses; while it is open Enter neither inserts a newline, nor continues a list, nor submits the surrounding form.

A runnable two-trigger example (# tags and / components) lives in the demo app's HomeLive.

Messages to Parent

Handle these in your LiveView's handle_info/2:

def handle_info({:leaf_changed, %{editor_id: id, markdown: md, html: html}}, socket) do
  # Content was updated
  {:noreply, assign(socket, :content, md)}
end

def handle_info({:leaf_insert_request, %{editor_id: id, type: :image}}, socket) do
  # User clicked the image toolbar button — show your image picker
  {:noreply, socket}
end

def handle_info({:leaf_mode_changed, %{editor_id: id, mode: mode}}, socket) do
  # Mode switched between :visual and :markdown
  {:noreply, socket}
end

def handle_info({:leaf_suggest, %{editor_id: id, trigger: t, query: q, seq: seq}}, socket) do
  # Only sent when `suggestions` is configured — see "Inline suggestions"
  {:noreply, socket}
end

Commands from Parent

# Insert an image at the cursor position
send_update(Leaf, id: "my-editor", action: :insert_image, url: "https://...", alt: "description")

# Replace all content
send_update(Leaf, id: "my-editor", action: :set_content, content: "# New content")

# Switch mode programmatically
send_update(Leaf, id: "my-editor", action: :set_mode, mode: :markdown)

# Answer a {:leaf_suggest, …} request (echo trigger/query/seq back unchanged)
send_update(Leaf,
  id: "my-editor",
  action: :suggestions,
  trigger: "#",
  query: "eli",
  seq: 7,
  results: [%{value: "elixir", label: "#elixir", sublabel: "12 posts", icon: "hero-hashtag"}]
)

Gettext (optional)

To enable translations for toolbar tooltips:

# config/config.exs
config :leaf, :gettext_backend, MyApp.Gettext

Without this config, English strings are used as-is.

License

MIT — see LICENSE.