@picadeck/core

Core package for Picadeck Schema Visualizer. Provides Express middleware, HTML renderer, types, and auto-layout for interactive database schema visualization.

Installation

npm install @picadeck/core

Usage with Express

import express from "express";
import { schemaVisualizer } from "@picadeck/core";
import { parseMongooseModels } from "@picadeck/mongoose-parser";
import { User, Post } from "./models";

const app = express();

app.use(
  "/schema",
  schemaVisualizer({
    parser: parseMongooseModels,
    models: [User, Post],
    theme: "dark",
    title: "My App Schema",
  })
);

app.listen(3000, () => {
  console.log("Visit http://localhost:3000/schema");
});

API

schemaVisualizer(options)

Creates Express middleware that serves an interactive schema visualizer.

Options:

| Option | Type | Required | Description | | -------- | --------------------------- | -------- | ------------------------------------ | | parser | ParserFunction | Yes | Parser function from any @picadeck parser package | | models | any[] | Yes | Array of models/schemas to visualize | | theme | 'light' \| 'dark' | No | UI theme (default: 'light') | | title | string | No | Page title |

generateHTML(schema, theme?)

Generates a self-contained HTML string with the embedded visualizer.

• schema — UniversalSchema object
• theme — 'light' | 'dark' (default: 'light')

calculateLayout(schema) / applyLayout(schema)

Utility functions for computing and applying automatic node positions.

Types

All parsers produce UniversalSchema, which contains:

• Entity — a table or collection with Field[], Index[], and Constraint[]
• Field — column definition with normalizedType, nullability, keys, defaults
• Relationship — one-to-one, one-to-many, or many-to-many link between entities
• NormalizedType — cross-framework type enum (STRING, INTEGER, BOOLEAN, JSON, UUID, etc.)

Features

• Light and dark theme support with CSS variables
• Interactive ReactFlow-based visualization (pan, zoom, drag)
• Automatic hierarchical layout algorithm
• Relationship mapping with cardinality indicators
• Single self-contained HTML response (no external requests)
• Schema injected via window.__PICADECK_SCHEMA__

License

MIT