Formatting Methods

This page covers the MDEditor methods that insert Markdown formatting: where they insert, how selections are handled, and when they emit HTML tags instead of Markdown markers.

Insert Position

Editor state	Behavior
Caret is inside the editor (with or without a selection)	Inserts at the caret; a selection is wrapped, and newlines inside it are removed
Caret was never placed	Appends to the last row; if the last row is empty, that row is rewritten

Afterwards the caret moves inside the markers and an undo entry is recorded; with autosave truthy the preview is updated too.

Markdown or HTML

The first argument of the inline methods is an event object, used to detect a held modifier key:

`event.metaKey` or `event.ctrlKey`	Output
False (toolbar click, or `{}` passed)	Markdown markers, e.g. `text`
True (triggered by a shortcut)	HTML tags, e.g. `<b>text</b>`

So Cmd/Ctrl+B inserts <b></b> while the toolbar button inserts ****. These methods read event.metaKey, so calling them without an argument throws a TypeError; pass {} from code.

Inline Formatting

Method	Markdown	HTML (modifier)
`bold(event)`	`text`	`<b>text</b>`
`italic(event)`	`text`	`<i>text</i>`
`strikethrough(event)`	`~~text~~`	`<s>text</s>`
`underline(event)`	`<u>text</u>`	`<u>text</u>`
`marker(event)`	`==text==`	`<mark>text</mark>`
`sup(event)`	`^text^`	`<sup>text</sup>`
`sub(event)`	`~text~`	`<sub>text</sub>`
`code(event)`	`text`	`<code>text</code>`

underline() has no Markdown form and always emits <u>. When the selection spans several rows, code() instead inserts a ``` row above and below it to form a code block.

Headings

editor.heading({}, 2);

Parameter	Description
`event`	As above; with a modifier the output is `<h2></h2>`
`num`	`1`-`6` map to `#`-`######`; `0` removes an existing `#` prefix

With a selection, the row's existing leading # and whitespace are stripped before the new level is applied.

Block Formatting

Method	Prefix per row	Without a caret
`blockquote()`	`>`	Appends a `>` row
`ul()`	`-`	Appends a `-` row
`ol()`	`1.`	Appends a `1.` row

With several rows selected, every row gets the prefix; ol() does not increment numbers, so every row is 1. and the rendered <ol> numbers them.

Links and Images

Method	Output	Ignored when
`link(title, href)`	`[title](href)`	Both `title` and `href` are empty
`image(src, alt, title)`	`![title or alt](src)`	`src` is empty

image() puts title inside the brackets and falls back to alt when it is empty; it never writes a Markdown "title" attribute. When inserting at the caret, a trailing space is added.