Markup

language.markup holds three helpers from IntelliJ: Emmet abbreviations, automatic end tags and paired tag renames. They work in html, xhtml, xml, svg, xsl, vue and php documents.

language.markup.supported; // whether the document is markup
language.markup.configure({ emmet: true, closeTags: true, linkedTags: true }); // each on unless false

Emmet

Tab after an abbreviation expands it through the emmet package. div>p>lipsum becomes a div with a paragraph of lorem ipsum, and ul>li.item$*3 a list of three numbered items. The expansion uses the editor's indentation and lands as a snippet, so Tab walks the places to fill and Escape ends it.

Tab only expands in document text, with a single caret and no selection. Tags, attribute values, comments, script, style, PHP code and Vue are excluded. A suggestion list, a running snippet, live templates and higher-priority handlers see Tab first. language.markup.expand() does the same for a menu and returns false when there was nothing to expand. language.markup.abbreviationAt() returns where the abbreviation Tab would expand starts, or null.

Wrap with an abbreviation

wrapWithAbbreviation has no default chord, since Mod+Alt+J is Surround with Live Template, whose first row is Emmet (see Surround With). language.markup.startWrap() opens a field over the selection, or over the caret's line. Enter wraps the text in the typed abbreviation. A repeat without a count, as in ul>li*, puts each line in its own element; otherwise the text goes in the innermost element. An invalid abbreviation keeps the field open with the reason. Escape or blur cancels. LanguagePopups draws the field; a host with its own reads wrap (WrapView) from language.popups and calls submitWrap(abbreviation) and cancelWrap().

Closing tags

The > that ends a start tag adds its end tag after the caret: <div class="card"> leaves <div class="card">|</div>. Void elements (br, img, input, ...), self-closing tags and an end tag that already follows get none. </ in text writes the end tag of the innermost open element. One undo removes the key and the tag.

Linked tags

Renaming a start tag renames its end tag, and the other way around, in one undo step. A space or a change outside the name ends the link.

Limits

A scanner reads the document, not a parser, so implied end tags (an li closing the one before) are unknown. Documents over 1,000,000 characters get no helpers. JSX and stylesheets are not covered.