diagram-drc

Design Rule Check engine for auto-generated diagrams.

Just as IC layout tools run DRC to catch spacing violations and routing issues in silicon, diagram-drc runs quality checks on graph layouts and can auto-fix violations.

Features

• Check mode — detect layout quality issues without modifying the diagram
• Fix mode — automatically resolve violations (crossing minimization, spacing, etc.)
• Pluggable rules — built-in rules for common issues, easy to add your own
• Format-agnostic core — works with any graph representation
• draw.io renderer — render layouts to mxGraph XML (draw.io format)
• Dagre layout — built-in wrapper for the Dagre directed graph layout engine

Quick start

npm install diagram-drc

import { createEngine, builtinRules, dagreLayout, renderMxGraph } from 'diagram-drc';

// Define your graph
const spec = {
  nodes: [
    { id: 'a', label: 'Service A', width: 48, height: 48 },
    { id: 'b', label: 'Service B', width: 48, height: 48 },
    { id: 'c', label: 'Database',  width: 48, height: 48 },
  ],
  edges: [
    { id: 'e1', source: 'a', target: 'c' },
    { id: 'e2', source: 'b', target: 'c' },
  ],
  groups: [
    { id: 'g1', label: 'Backend', children: ['a', 'b'] },
    { id: 'g2', label: 'Data',    children: ['c'] },
  ],
};

// Layout with Dagre
const layout = dagreLayout(spec);

// Run DRC — check for issues
const engine = createEngine({ rules: builtinRules() });
const report = engine.check(layout, spec);
console.log(report.passed ? 'All checks passed' : `${report.violations.length} violation(s)`);

// Or fix issues automatically
const { layout: fixed, report: fixReport } = engine.fix(layout, spec);

// Render to draw.io
const xml = renderMxGraph(fixed, spec, { title: 'Architecture' });

Built-in rules

| Rule | Description | |------|-------------| | crossing-minimization | Reorders sibling nodes within groups to minimize edge crossings | | spacing | Ensures minimum distance between node bounding boxes |

Writing custom rules

import type { LayoutRule, LayoutResult, GraphSpec, Violation } from 'diagram-drc';

const myRule: LayoutRule = {
  id: 'my-custom-rule',
  description: 'Check something specific to my diagrams',
  severity: 'warning',
  check(layout, spec) {
    // Return violations found
    return [];
  },
  fix(layout, spec) {
    // Return corrected layout
    return layout;
  },
};

engine.addRule(myRule);

API

Engine

• createEngine(options?) — create a DRC engine
• engine.check(layout, spec) — detect violations (read-only)
• engine.fix(layout, spec) — fix violations and report remaining issues
• engine.addRule(rule) — add a rule (chainable)

Layout

• dagreLayout(spec, options?) — run Dagre layout on a graph

Render

• renderMxGraph(layout, spec, options?) — render to draw.io mxGraph XML

License

MIT