Spoilers

A room discussing a film, a game or a book has no way to say something without saying it to everyone who scrolls past. Discord's answer is the spoiler: text wrapped in || bars, or a message sent through /spoiler, renders as a dark bar until a reader clicks it, and an attachment marked with the upload preview's eye icon is blurred behind a SPOILER label until it is opened. It is one of the most-used pieces of Discord's message markup, and Esbabbler, which matches Discord by default (esbabbler), has none of it.

What it adds

Text

• A spoiler mark in the composer's Tiptap schema, rendered as <span data-spoiler>. Typing ||text|| converts the wrapped text as the closing bars are typed (a mark input rule, the way StarterKit's **bold** rule works); Ctrl+Shift+S, a formatting-toolbar button and /spoiler <text> apply it too. /spoiler joins the slash-command registry as a text-transform command like /shrug (slash commands).
• Rendering. A spoiler span draws as a filled bar in the muted text colour with its text transparent, role="button", tabindex="0" and aria-label="Spoiler, activate to reveal"; a click, Enter or Space reveals it for that reader, in that message, until the room is left. Revealing is client state only — nothing is written.
• The sanitizer allows the one attribute: sanitizeTextHtml adds data-spoiler to span's allowed attributes, the same way the mention and custom-emoji attributes are allowed. Link previews are not generated for a URL inside a spoiler, since the preview card would print what the bar hides.
• Push and search. A push body replaces spoiler text with ▇▇▇▇, so a lock screen does not reveal it; search still matches the text, since the searcher typed it.

Attachments

• Mark as spoiler is a toggle on each pending attachment in the composer, beside its remove button, and the file entity gains isSpoiler. An image or video renders blurred with a SPOILER label over it until clicked, and a spoiler image opens in the lightbox only after that first click. A file whose name starts SPOILER_ is marked on upload, as Discord does, so a file renamed elsewhere keeps its intent.

flowchart LR
  TYPE["||text|| · /spoiler · Ctrl+Shift+S"] --> MARK[spoiler mark]
  ATTACH["pending attachment · eye toggle or SPOILER_ name"] --> FLAG[isSpoiler on the file entity]
  MARK --> SAN["sanitizeTextHtml keeps data-spoiler"]
  SAN --> RENDER[bar, click to reveal]
  FLAG --> BLUR[blurred, click to reveal]
  MARK -->|push body| MASK["text masked"]

What is deliberately not in it

• No "show spoiler content" setting (Discord's always / on servers I moderate / on click). One behaviour — click to reveal — until someone asks for another.
• No spoiler on a whole message's embeds or polls. Text and attachments are what people hide.

Key files

Sources

• How-To Geek — how to use spoiler tags on Discord — the || syntax, /spoiler, the eye icon on an upload and click-to-reveal (Discord's own help article refuses automated readers).
• MarkdownTools — Discord spoiler tags — the SPOILER_ file-name prefix Discord detects to hide an attachment.