• x9.playground lets you create interactive playgrounds (Similar to Swift Playgrounds, Scala Worksheets, or Quokka.js).
• playgrounds can be created within any file, and they are always ignored when bundling code

function sum(a, b) {  return a + b;}x9.playground(() => {  sum(1, 2);});

You an also create playgrounds by adding a top-level block.

function sum(a, b) {  return a + b;}{  sum(1, 2);}

Top-level blocks are the preferred syntax. But x9.playground() exposes more configuration options.

Execution Model

We need to figure this out. There are many options:

• all blocks on all open documents
• all blocks on visible documents

Overriding:

• // only will run only the focused playground
• // skip will skip playground, even if it matches all other rules