Generate da-commitment package and publish

• cargo install wasm-pack
• chmod +x ./build_package.sh
• ./build_package.sh <x.x.x> (eg. ./build_package.sh 0.1.0)
• If there is an issue: https://github.com/wasm-bindgen/wasm-bindgen/issues/4228#issuecomment-2693647441

Usage

build_commitments_js(data, params_version, babe_randomness, blob_hash) returns:

• commitment
• eval_point_seed
• eval_claim

Simple Node usage:

import { build_commitments_js } from "da-commitment-node";
import { keccakAsU8a } from "@polkadot/util-crypto";

const text = "Hello World!";
const encoder = new TextEncoder();
const data = encoder.encode(text);
const paramsVersion = 0;
const babeRandomness = new Uint8Array(32); // replace with real BABE randomness from chain
const blobHash = keccakAsU8a(data);

const metadata = build_commitments_js(data, paramsVersion, babeRandomness, blobHash);

console.log(Buffer.from(metadata.commitment).toString("hex"));

Standalone build

If you just want to build locally by hand:

cd utils/da-commitment-js
cargo install wasm-pack
wasm-pack build --target nodejs --features wasm
mv pkg pkg_node

After that, the local Node package is in pkg_node.

JS example

There is a small JS example in examples/submit_blob_metadata.cjs.

It shows how to:

• compute the FRI metadata with build_commitments_js
• build dataAvailability.submitBlobMetadata
• sign it
• submit it with blob_submitBlob

You can tweak the constants at the top of the file if needed, for example:

• WS_URL
• TEXT
• APP_ID
• ERA_PERIOD

Install and run:

cd utils/da-commitment-js/examples
npm install @polkadot/api @polkadot/keyring @polkadot/util @polkadot/util-crypto
node submit_blob_metadata.cjs