Markdown parsed where it is typed

DOM/markdown parses markdown in the browser. parse_markdown(src) returns HTML, which makes a live preview a two-line affair.

onExist('#editor', el => on('input', el, () => obj('#preview').innerHTML = parse_markdown(el.value)))

It exists because a preview is the one case where a round trip is genuinely wrong. Every other rendering job in Phlo belongs on the server: the server has the data, the escaping rules and the templates, and a route returning HTML through apply() is simpler than any client equivalent. But a preview updates on every keystroke, and no amount of server speed makes that the right shape.

It covers more than the marks people type in a comment: headings with anchors, bold, italic, code, links, lists, quotes, fenced blocks, tables and task lists. Server-side rendering of stored markdown stays a separate concern, which is where this site uses a PHP parser for its own posts.

The pairing worth noticing is with the fields layer. A wysiwyg field gives an editor that writes HTML; markdown plus a preview gives a plain textarea that stores text. For anything a user might later export, diff or edit somewhere else, the second one ages better.

Engine 1.0. See markdown in the manual.