@ifc-lite/flow

Keyed-data graph runtime for BIM workflows: the engine behind ifc-lite's node graphs. Pure TypeScript, no DOM, no SDK dependency — the same graph evaluates in the browser viewer and in the headless CLI.

What it does

• One data model. Every value on an edge is an Item, a List, or a Group (lists keyed by string: GlobalId, storey, sheet name, grid intersection). Tables carry typed columns with IFC value types, units and the property they were read from.
• Lifting instead of data trees. A port declares item, list or group access. The scheduler lifts a node over lists by lacing (shortest, longest, cross) and over groups by key — branches match when their keys are equal, never by position. Unmatched keys are reported, not silently dropped.
• Memoised evaluation. Topological order, content-digested inputs, per-model revisions for nodes that read the model, a structured run log with per-lane errors.
• Element tracking. A write node's output survives re-runs: GlobalIds are derived from a user-visible tracking key and the lane key, vanished lanes are removed, and the tracked set is pinned to the model state it was made against.
• Documents. *.flow.json is git-diffable, hand-validated, and migrated by version.

Install

npm install @ifc-lite/flow

Usage

import { NodeRegistry, runFlow, parseFlowDocument, list } from '@ifc-lite/flow';

const registry = new NodeRegistry<{ names: string[] }>().register({
  type: 'demo.upper',
  title: 'Upper-case',
  category: 'demo',
  inputs: [{ name: 'text', type: { kind: 'scalar', access: 'item' } }],
  outputs: [{ name: 'upper', type: { kind: 'scalar', access: 'item' } }],
  params: [],
  capabilities: [],
  run: (_ctx, inputs) => ({ upper: String(inputs.text).toUpperCase() }),
});

const doc = parseFlowDocument(JSON.stringify({
  flowVersion: 1, id: 'demo', name: 'demo', capabilities: [], inputs: [], outputs: [],
  nodes: [{ id: 'u', type: 'demo.upper' }], edges: [],
}));

const result = await runFlow(doc, { host: { names: [] }, registry });
console.log(result.ok, result.reports);

Node libraries over the ifc-lite SDK live in @ifc-lite/flow-nodes.

License

MPL-2.0