@ifc-lite/codegen

TypeScript code generator for IFC EXPRESS schemas. Parses official .exp schema files from buildingSMART and emits typed TypeScript: 1000+ entity interfaces with full inheritance, schema metadata for runtime introspection, and exhaustive enum unions.

This is a build-time tool — you don't depend on it at runtime. The generated output ships with @ifc-lite/parser.

Installation

npm install --save-dev @ifc-lite/codegen

Generate from the official IFC schema

# IFC4 (776 entities)
node dist/cli.js schemas/IFC4_ADD2_TC1.exp --output ./generated/ifc4

# IFC4X3 (876 entities, includes infrastructure: roads, bridges, alignments)
node dist/cli.js schemas/IFC4X3.exp --output ./generated/ifc4x3

Pass --rust to also emit Rust type tables (consumed by the ifc-lite Rust core).

Generated files (one per output directory, e.g. ./generated/ifc4):

generated/ifc4/
├── entities.ts          ← TypeScript interfaces for every entity
├── types.ts             ← defined-type aliases
├── enums.ts             ← enum definitions
├── selects.ts           ← SELECT union types
├── schema-registry.ts   ← runtime metadata (parent, attributes, ...)
├── type-ids.ts          ← numeric type-id lookup tables
├── serializers.ts       ← STEP serializer bound to the schema registry
└── index.ts             ← barrel export

Programmatic usage

import { parseExpressSchema, generateTypeScript } from '@ifc-lite/codegen';
import { readFile, writeFile } from 'node:fs/promises';

const schema = parseExpressSchema(await readFile('./schemas/IFC4.exp', 'utf-8'));

console.log(`Parsed ${schema.entities.length} entities, ${schema.types.length} types`);

const generated = generateTypeScript(schema);

await writeFile('./generated/ifc4/entities.ts', generated.entities);
await writeFile('./generated/ifc4/schema-registry.ts', generated.schemaRegistry);

What you get

For an EXPRESS entity like:

ENTITY IfcWall
  SUBTYPE OF (IfcBuildingElement);
  PredefinedType : OPTIONAL IfcWallTypeEnum;
END_ENTITY;

You get a TypeScript interface with full inheritance:

export interface IfcWall extends IfcBuildingElement {
  PredefinedType?: IfcWallTypeEnum;
}

Plus runtime metadata for the same entity:

SCHEMA_REGISTRY.IfcWall = {
  parent: 'IfcBuildingElement',
  inheritanceChain: ['IfcRoot', 'IfcObjectDefinition', /* ... */, 'IfcWall'],
  attributes: [
    { name: 'PredefinedType', type: 'IfcWallTypeEnum', optional: true },
  ],
  allAttributes: [/* every inherited attribute, in inheritance order */],
};

Why generate vs. hand-write

• Coverage: 776 IFC4 entities and 876 IFC4X3 entities — manual implementation gets ~7% there.
• Updates: when buildingSMART releases a new schema, regenerate; no manual edits.
• Consistency: every entity follows the same shape. Types, names, optional-ness all match the spec exactly.
• Type safety: TypeScript catches schema-violating attribute access at compile time.

API

See the API Reference.

License

MPL-2.0