Node Env Demo

A canvas-local node_modules for Node, following the same meshfox:var from= pattern as python-venv.canvas.md: the node-setup block below installs this demo's one dependency into .meshfox/node-env.canvas.md.node/ (once — it is skipped until the declared packages change) and reports a launcher for node as the computed NODE variable. Every Node-running fence references it via interpreter="$NODE" instead of needing an npm install next to the canvas, so the document carries everything it needs.

That interpreter= reference is also the only ordering this canvas needs: a from=-declared variable's source block is an implicit dependency of anything that resolves it, so render below has no deps= of its own.

Environment setup

interpreter="@node_env" is a built-in interpreter, like @python_venv. A text fence lists npm packages, one per line (pele, left-pad@1.3.0, @scope/pkg@^2; blank lines and # comments are skipped); a json fence is a whole package.json instead. The launcher it reports runs the node on your PATH with this environment's packages visible to both require and import (Node 20.6 or newer). Relative imports (./helper.js) are a different matter — those resolve from where the code's file lives, which is what a block's tangle flag is for.

pele@1.6.0

Rendering a Mermaid diagram

Pele is a small pure-JS Mermaid renderer — no browser, a few milliseconds per diagram. It is young and draws with its own layout and style, so a diagram can look different from mmdc's. The block prints the SVG and output="image" shows it as a picture (see svg.canvas.md).

import { render } from "pele";

const { svg } = render(`flowchart LR
  A[Block] -->|prints SVG| B(output=image) --> C{{Picture}}`);
process.stdout.write(svg);