@schema-first/core

A strictly typed, framework-agnostic data specification engine. Define your domain logic, permissions, and API actions once; render them anywhere.

🎯 Goals

• Single Source of Truth: Define labels, validation, and API logic in the "Spec," not the UI.
• Strict Framework Interop: Use the TypeRegistry to swap React components for Vue/Svelte nodes without losing type safety.
• Convention over Configuration: Automatically infer labels and URLs while allowing deep overrides.
• Zero UI Dependency: The core package manages the logic of data; your UI package manages the pixels.

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⚙️ Configuration & Customization

1. The Type Registry (Framework Interop)

If you are using something other than React, or want to lock down your API paths, use Declaration Merging in a spec.d.ts file:

import "@schema-first/core";

declare module "@schema-first/core" {
  interface TypeRegistry {
    element: MyVueVNode; // Swap ReactNode
    icon: MyIconComponent;
    resource_key: "User" | "Project" | "Invoice"; // Strict keys
  }

  interface ColumnMetadataRegistry {
    isInternal: boolean; // Add custom column props
  }
}

2. Initializing Conventions

Initialize the engine at your app's entry point to inject icons and fetch logic.

import {
  initializeConventions,
  labels,
  urls,
  auto_pages,
} from "@schema-first/core";
import { FiPlus, FiTrash } from "react-icons/fi";

initializeConventions({
  UNIMPLEMENTED_PLACEHOLDER: <i>Not yet implemented</i>,
  actions: {
    create: { label: "Add {resource}", icon: FiPlus },
    delete: { label: "Remove", icon: FiTrash, color: "red" },
  },
  fetch: async (url, method, body) => {
    const res = await fetch(url, { method, body: JSON.stringify(body) });
    return res.json();
  },
  labels,
  urls,
  auto_pages,
  loadSpec: (name) => myCachedSpecs[name],
  SORTABLE_FIELDS: ["string", "number", "datetime"],
});

---

🎨 The Renderer System

The RegisteredRenderer system is the bridge between your Spec and your UI Library. It allows you to register components for specific data types and view modes (Table, Form, etc.).

Registering a Custom Renderer

If you have a custom "Markdown" type or want to override how "Currency" looks in a table:

import { registerRenderer } from "@schema-first/core";

// Register a custom table renderer for currency
registerRenderer("number", {
  view: "table",
  test: (spec) => spec.numberType === "currency",
  renderer: ({ data, meta }) => (
    <span className="font-mono">
      {meta.currency} {data.toLocaleString()}
    </span>
  ),
});

Consuming Renderers in UI

In your components, use getRenderer to resolve the correct component based on the spec.

const ColumnCell = ({ spec, data }) => {
  // Finds the best match in the Registry (or returns the Placeholder)
  const Renderer = getRenderer(spec, "table");

  return <Renderer data={data} spec={spec} meta={spec.meta} />;
};

---

📊 Using in Tables

The Spec provides everything needed to build high-performance data tables. Use tableColumns to iterate through keys.

const { tableColumns, columns } = UserSpec;

return (
  <table>
    <thead>
      <tr>
        {tableColumns.map((key) => (
          <th key={key}>{columns[key].label}</th>
        ))}
      </tr>
    </thead>
    <tbody>
      {data.map((row) => (
        <tr key={row.id}>
          {tableColumns.map((key) => (
            <td key={key}>
              <ColumnCell spec={columns[key]} data={row[key]} />
            </td>
          ))}
        </tr>
      ))}
    </tbody>
  </table>
);

---

📝 Using in Forms

The RawColumnSpec handles validation and field types. Use the form property on Actions to render dynamic modals or pages.

const CreateUserAction = new APIAction({
  method: "POST",
  form: UserSpec, // The form is driven by the UserSpec columns
  label: "Create User",
  execute: async (data) => {
    /* ... */
  },
});

// In your Form Component:
{
  Object.entries(UserSpec.columns).map(([key, col]) => {
    if (!col.showOnForm) return null;
    const Input = getRenderer(col, "form");
    return <Input key={key} spec={col} />;
  });
}

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License

This project is licensed under the Apache License 2.0 - see the LICENSE and NOTICE files for details.