JavaScript Example

How to Submit a Proof

Follow the instructions below to submit a proof using JavaScript. This example demonstrates submission of different proof types and their events.

Prerequisites

Before you begin, ensure you have Node.js installed on your machine. You can download and install it from the official Node.js website.

Installing Node.js

1. Download Node.js:

   • Visit the Node.js download page.
   • Download the LTS (Long Term Support) version for your operating system.

2. Install Node.js:

   • Run the downloaded installer and follow the instructions.
   • Ensure that the installer includes npm (Node Package Manager).

3. Verify Installation:

   • Open a terminal or command prompt.

   • Run the following commands to verify that Node.js and npm are installed correctly:

     node -v
     npm -v

   • You should see the version numbers of Node.js and npm.

Now you are ready to follow the instructions below to submit a proof.

Initialize Your Project

1. Create a new directory for your project, navigate into it:

   mkdir my-zkverify-project
   cd my-zkverify-project

2. Initialize a new npm project:

   npm init -y

3. Install the required packages:

   npm install @polkadot/api @polkadot/keyring dotenv

4. Create a .env file:

   echo -e "WEBSOCKET=wss://testnet-rpc.zkverify.io\nPRIVATE_KEY=your_private_key" > .env

5. Update the .env file values:

   • WEBSOCKET: The zkVerify Websocket url
   • PRIVATE_KEY: Your testnet seedphrase enclosed in quotation marks

Example Script

Create a file named submitProof.js and paste the following script into it:

require('dotenv').config();
const { ApiPromise, WsProvider } = require('@polkadot/api');
const { Keyring } = require('@polkadot/keyring');

const proofs = {
   fflonk: { pallet: 'settlementFFlonkPallet' },
   boojum: { pallet: 'settlementZksyncPallet' }
};

const requiredEnvVariables = ['WEBSOCKET', 'PRIVATE_KEY'];
requiredEnvVariables.forEach((envVar) => {
   if (!process.env[envVar]) {
      throw new Error(`Required environment variable ${envVar} is not set.`);
   }
});

const proofType = process.argv[2];
const proof = process.argv[3];

if (!proofType || !proof) {
   throw new Error('Please provide both proof type and proof as command line arguments.');
}

if (!proofs[proofType]) {
   throw new Error('Invalid proof type. Valid proof types are: fflonk, boojum.');
}

(async () => {
   let api;
   let provider;
   let interval;
   let startTime = Date.now();

   try {
      provider = new WsProvider(process.env.WEBSOCKET);
      api = await createApi(provider);

      const keyring = new Keyring({ type: 'sr25519' });
      const account = keyring.addFromUri(process.env.PRIVATE_KEY);

      console.log(`Submitting ${proofType} proof...`);
      const submitProof = api.tx[proofs[proofType].pallet].submitProof(proof);

      let proof_leaf = null;
      let attestation_id = null;

      await new Promise((resolve, reject) => {
         submitProof.signAndSend(account, async ({ events, status, dispatchError }) => {
            let elapsed = (Date.now() - startTime) / 1000;

            if (status.isInBlock) {
               console.log(`Transaction included in block (elapsed time: ${elapsed} seconds)`);
               handleEvents(events, (data) => {
                  proof_leaf = data[0].toString();
                  attestation_id = data[1].toString();
                  console.log(`Proof Verified:\n  - Attestation Id: ${attestation_id}\n  - Proof Leaf: ${proof_leaf}`);
               });

               if (dispatchError) {
                  console.error(`Invalid ${proofType} transaction:`, dispatchError.toString());
                  reject(dispatchError);
               } else {
                  resolve();
               }

               interval = setInterval(() => {
                  let elapsed = (Date.now() - startTime) / 1000;
                  console.log(`Waiting for ${proofType} transaction to finalize... (elapsed time: ${elapsed} seconds)`);
               }, 5000);
            }

            if (status.isFinalized) {
               clearInterval(interval);
               console.log(`Block containing ${proofType} proof transaction finalized (elapsed time: ${elapsed} seconds)`);
            }
         });
      });

      await waitForAttestationId(attestation_id);

      console.log(`Waiting for NewAttestation event...`);
      await waitForNewAttestation(api, 360000, attestation_id, startTime);
   } catch (error) {
      handleError(error);
      if (provider) provider.disconnect();
   } finally {
      if (api) await api.disconnect();
   }
})();

async function createApi(provider) {
   const timeout = new Promise((_, reject) =>
           setTimeout(() => reject(new Error('Failed to connect to the WebSocket URL.')), 3000)
   );
   return await Promise.race([ApiPromise.create({ provider }), timeout]);
}

function handleEvents(events, callback) {
   events.forEach(({ event: { data, method, section } }) => {
      if (section === 'poe' && method === 'NewElement') {
         callback(data);
      }
   });
}

async function waitForAttestationId(attestation_id) {
   while (!attestation_id) {
      console.log("Waiting for attestation_id to be set...");
      await new Promise(resolve => setTimeout(resolve, 1000));
   }
}

async function waitForNewAttestation(api, timeoutDuration, attestation_id, startTime) {
   return new Promise(async (resolve, reject) => {
      const timeout = setTimeout(() => {
         unsubscribe();
         reject("Timeout expired");
      }, timeoutDuration);

      const interval = setInterval(() => {
         let elapsed = (Date.now() - startTime) / 1000;
         console.log(`Waiting for NewAttestation event... (elapsed time: ${elapsed} seconds)`);
      }, 15000);

      const unsubscribe = await api.query.system.events((events) => {
         events.forEach((record) => {
            const { event } = record;
            const types = event.typeDef;

            if (event.section === "poe" && event.method === "NewAttestation") {
               const currentAttestationId = event.data[0].toString();
               console.log(`Detected NewAttestation event with id: ${currentAttestationId}`);
               if (currentAttestationId === attestation_id) {
                  clearTimeout(timeout);
                  clearInterval(interval);
                  unsubscribe();
                  console.log(`Matched NewAttestation event with ProofVerified event Attestation Id ${attestation_id}:`);
                  event.data.forEach((data, index) => {
                     console.log(`\t${types[index].type}: ${data.toString()}`);
                  });
                  resolve(event.data);
               }
            }
         });
      });
   });
}

function handleError(error) {
   if (error.message.includes('Invalid bip39 mnemonic specified')) {
      console.error('Failed to create account from the provided PRIVATE_KEY. Please check the PRIVATE_KEY environment variable.');
   } else {
      console.error(`An error occurred: ${error.message}`);
   }
}

Running the Script

Run the script by providing 2 arguments: proof type and proof. You should see the transaction successfully finalized and a NewAttestationEvent emitted.

node submitProof.js <proofType> <proof>

Working Examples

Fflonk:

node submitProof.js fflonk 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

Boojum (zkSync Era)

node submitProof.js boojum 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

Further Examples

Other javascript examples can be found in the e2e tests