@lof-lang/toolkit-browser

Browser-friendly helpers for wiring Lof circuits into web applications. This package is designed to sit on top of the artifacts generated by lof compile … --target wasm, orchestrating the witness calculator and prover WASM modules without requiring a bespoke integration script.

⚠️ The WASM bindings themselves (e.g. prover/lofit.js) are expected to be generated by wasm-pack as part of the circuit packaging workflow. This package provides typed glue code and ergonomic APIs for loading and using those bindings.

Installation

npm install @lof-lang/toolkit-browser

You also need the circuit-specific assets produced by:

lof compile path/to/circuit.lof --target wasm --output web/circuit

which yields directories such as build/, keys/, witness/, and prover/.

Quick start

Simple (auto-discovery)

The easiest way to use the toolkit is to specify bundleRoot, which automatically discovers all circuit artifacts:

import { createLofCircuit } from '@lof-lang/toolkit-browser';

const circuit = await createLofCircuit({
  bundleRoot: '/circuits/multiply',  // Points to your compiled circuit bundle
  publicSignals: ['a', 'b'],
  witnessSignals: ['c']
});

const { proofBytes, publicInputs } = await circuit.generateProof({
  a: '5',
  b: '7',
  c: '35'
});

With bundleRoot, the toolkit automatically constructs paths:

• ${bundleRoot}/build/${circuitName}.r1cs
• ${bundleRoot}/keys/${circuitName}_pk.bin
• ${bundleRoot}/witness/${circuitName}_witness_wasm.js
• ${bundleRoot}/prover/lofit.js

The circuit name is inferred from the last path segment of bundleRoot (e.g., /circuits/multiply → multiply).

Explicit URLs

For full control, you can specify each URL individually:

const circuit = await createLofCircuit({
  publicSignals: ['a', 'b'],
  witnessSignals: ['c'],
  r1csUrl: '/circuit/build/circuit.r1cs',
  provingKeyUrl: '/circuit/keys/circuit_pk.bin',
  loadWitnessModule: () => import('/circuit/witness/circuit_witness_wasm.js'),
  loadProverModule: () => import('/circuit/prover/lofit.js'),
});

const { proofBytes, publicInputs } = await circuit.generateProof(userInputs);

All URLs are served relative to your web app. The publicSignals / witnessSignals arrays describe the signal order.

API

createLofCircuit(options)

Loads the WASM modules, fetches the R1CS and proving key, and returns a circuit instance.

Options:

• publicSignals: string[] – Ordered list of public input signal names (required)
• witnessSignals: string[] – Ordered list of private witness signal names (required)
• bundleRoot?: string – Base URL where circuit bundle is served (enables auto-discovery)
• artifactName?: string – Circuit name (defaults to last segment of bundleRoot)
• r1csUrl?: string – Explicit R1CS file URL (overrides auto-discovery)
• provingKeyUrl?: string – Explicit proving key URL (overrides auto-discovery)
• witnessModuleUrl?: string – Explicit witness WASM module URL
• proverModuleUrl?: string – Explicit prover WASM module URL
• loadWitnessModule?: () => Promise<WitnessModule> – Custom witness module loader
• loadProverModule?: () => Promise<ProverModule> – Custom prover module loader
• r1cs?: Uint8Array – Pre-loaded R1CS bytes (for offline use)
• provingKey?: Uint8Array – Pre-loaded proving key bytes (for offline use)

Returns a circuit instance with:

• generateProof(inputs) – computes the witness, builds ordered inputs, and invokes the prover
• buildWitnessArray(witness) – helper for packing witness objects into ordered arrays
• buildPublicInputs(witness) – converts witness output into a JSON-ready public input object
• computeWitness(inputs) – wraps the witness calculator for reuse or debugging
• getProver() – access to the underlying WASM prover instance

See the inline TypeScript docs for the full contract.