Quick start (JavaScript)

Create your first DApp and run it on local blockchain

• Prerequisites

• Prepare development environment

• Start local node (SE)

• Install demo application

• What the script does

• Sample code

• Run it!

• Source code

Prerequisites

Node.js latest version installed Docker latest version installed

Prepare development environment

Install EVERDEV CLI that will help you easily start local node, compile your contracts, install demo projects and create new empty projects.

$ npm install -g everdev

Start local node (SE)

We will run our test on local blockchain for testing (Evernode SE, start it with this command (docker should be launched).

$ everdev se start

Install demo application

Create a working folder. Then create a node.js demo project with EVERDEV

$ everdev js demo hello-wallet
$ cd hello-wallet
$ npm i

What the script does

The script implements the following logic:

1. Links the project with Node.js Ever-SDK binary. If you plan to use JS SDK in Web, link it with Wasm binary. Read more here.

2. TONClient instance is created and initialized with Evernode SE ("http://localhost", local blockchain) endpoint. See the list of other available endpoints.

3. Future address is calculated from the code and data of the contract (data includes signing keys)

4. Flag useGiver: true allows to sponsor deploy with Evernode SE giver that is hard coded as the default Account giver. You can re-assign it to your own giver.

Sample code

Core API Implementation

(async () => {
    try {
        // Generate an ed25519 key pair
        const walletKeys = await client.crypto.generate_random_sign_keys();

        // Calculate future wallet address.
        const walletAddress = await calcWalletAddress(walletKeys);

        // Send some tokens to `walletAddress` before deploy
        await getTokensFromGiver(walletAddress, 1_000_000_000);

        // Deploy wallet
        await deployWallet(walletKeys);

        // Get wallet's account info and print balance
        const accountState = await getAccount(walletAddress);
        console.log("Hello wallet balance is", accountState.balance)

        // Run account's get method `getTimestamp`
        let walletTimestamp = await runGetMethod('getTimestamp', walletAddress, accountState.boc );
        console.log("`timestamp` value is", walletTimestamp)

        // Perform 2 seconds sleep, so that we receive an updated timestamp
        await new Promise(r => setTimeout(r, 2000));
        // Execute `touch` method for newly deployed Hello wallet contract
        // Remember the logical time of the generated transaction
        let transLt = await runOnChain(walletAddress, "touch");

        // Run contract's get method locally after account is updated
        walletTimestamp = await runGetMethodAfterLt('getTimestamp', walletAddress, transLt);
        console.log("Updated `timestamp` value is", walletTimestamp)

        // Send some tokens from Hello wallet to a random account
        // Remember the logical time of the generated transaction
        const destAddress = await genRandomAddress();
        transLt = await sendValue(walletAddress, destAddress, 100_000_000, walletKeys);

        console.log('Normal exit');
        process.exit(0);
    } catch (error) {
        if (error.code === 504) {
            console.error(
                [
                    'Network is inaccessible. You have to start Evernode SE using `everdev se start`',
                    'If you run SE on another port or ip, replace http://localhost endpoint with',
                    'http://localhost:port or http://ip:port in index.js file.',
                ].join('\n'),
            );
        } else {
            console.error(error);
            process.exit(1);
        }
    }
})();

async function calcWalletAddress(keys) {
    // Get future `Hello`Wallet contract address from `encode_message` result
    const { address } = await client.abi.encode_message(buildDeployOptions(keys));
    console.log(`Future address of Hello wallet contract is: ${address}`);
    return address;
}

function buildDeployOptions(keys) {
    // Prepare parameters for deploy message encoding
    // See more info about `encode_message` method parameters here:
    // https://github.com/tonlabs/ever-sdk/blob/master/docs/reference/types-and-methods/mod_abi.md#encode_message
    const deployOptions = {
        abi: {
            type: 'Contract',
            value: HelloWallet.abi,
        },
        deploy_set: {
            tvc: HelloWallet.tvc,
            initial_data: {},
        },
        call_set: {
            function_name: 'constructor',
            input: {},
        },
        signer: {
            type: 'Keys',
            keys,
        },
    };
    return deployOptions;
}

// Request funds from Giver contract
async function getTokensFromGiver(dest, value) {
    console.log(`Transfering ${value} tokens from giver to ${dest}`);

    const params = {
        send_events: false,
        message_encode_params: {
            address: GIVER_ADDRESS,
            abi: abiContract(GIVER_ABI),
            call_set: {
                function_name: 'sendTransaction',
                input: {
                    dest,
                    value,
                    bounce: false,
                },
            },
            signer: {
                type: 'Keys',
                keys: GIVER_KEYS,
            },
        },
    };
    await client.processing.process_message(params);
    console.log('Success. Tokens were transfered\n');
}

async function deployWallet(walletKeys) {
    // Deploy `Hello wallet` contract
    // See more info about `process_message` here:
    // https://github.com/tonlabs/ever-sdk/blob/master/docs/reference/types-and-methods/mod_processing.md#process_message
    console.log('Deploying Hello wallet contract');
    await client.processing.process_message({
        send_events: false,
        message_encode_params: buildDeployOptions(walletKeys),
    });
    console.log('Success. Contract was deployed\n');
}

async function runOnChain(address, methodName) {
    // Encode the message with external call
    const params = {
        send_events: false,
        message_encode_params: {
            address,
            abi: {
                type: 'Contract',
                value: HelloWallet.abi,
            },
            call_set: {
                function_name: methodName,
                input: {},
            },
            signer: signerNone(),
        },
    };
    console.log(`Calling ${methodName} function`);
    const response = await client.processing.process_message(params);
    const { id, lt } = response.transaction;
    console.log('Success. TransactionId is: %s\n', id);
    return lt;
}


// Sometimes it is needed to execute getmethods after on-chain calls.
// This means that the downloaded account state should have the changes made by the on-chain call. 
// To ensure it, we need to remember the transaction lt (logical time) of the last call
// and then wait for the account state to have lt > the transaction lt. 
// Note that account.last_trans_lt is always bigger than transaction.lt because this field stores the end lt of transaction interval
// For more information about transaction lt interval read TON Blockchain spec https://test.ton.org/tblkch.pdf P. 4.2.1
async function waitForAccountUpdate(address, transLt) {
    console.log('Waiting for account update');
    const startTime = Date.now();
    const account = await client.net.wait_for_collection({
        collection: 'accounts',
        filter: {
            id: { eq: address },
            last_trans_lt: { gt: transLt },
        },
        result: 'boc',
    });
    const duration = Math.floor((Date.now() - startTime) / 1000);
    console.log(`Success. Account was updated, it took ${duration} sec.\n`);
    return account;
}


async function getAccount(address) {

    // `boc` or bag of cells - native blockchain data layout. Account's boc contains full account state (code and data) that
    // we will  need to execute get methods.
    const query = `
        query {
          blockchain {
            account(
              address: "${address}"
            ) {
               info {
                balance(format: DEC)
                boc
              }
            }
          }
        }`
    const {result}  = await client.net.query({query})
    const info = result.data.blockchain.account.info
    return info
}
async function runGetMethod(methodName, address, accountState) {
    // Execute the get method `getTimestamp` on the latest account's state
    // This can be managed in 3 steps:
    // 1. Download the latest Account State (BOC) 
    // 2. Encode message
    // 3. Execute the message locally on the downloaded state

    // Encode the message with `getTimestamp` call
    const { message } = await client.abi.encode_message({
        // Define contract ABI in the Application
        // See more info about ABI type here:
        // https://github.com/tonlabs/ever-sdk/blob/master/docs/reference/types-and-methods/mod_abi.md#abi
        abi: {
            type: 'Contract',
            value: HelloWallet.abi,
        },
        address,
        call_set: {
            function_name: methodName,
            input: {},
        },
        signer: { type: 'None' },
    });

    // Execute `getTimestamp` get method  (execute the message locally on TVM)
    // See more info about run_tvm method here:
    // https://github.com/tonlabs/ever-sdk/blob/master/docs/reference/types-and-methods/mod_tvm.md#run_tvm
    console.log('Run `getTimestamp` get method');
    const response = await client.tvm.run_tvm({
        message,
        account: accountState,
        abi: {
            type: 'Contract',
            value: HelloWallet.abi,
        },
    });
    return response.decoded.output
}


async function runGetMethodAfterLt(methodName, address, transLt) {
    // Wait for the account state to be more or equal the spesified logical time
    const accountState = await waitForAccountUpdate(address, transLt).then(({ result }) => result.boc);
    const result = await runGetMethod(methodName, address, accountState);
    return result;
    
}

async function sendValue(address, dest, amount, keys) {
    // Encode the message with `sendValue` function call
    const sendValueParams = {
        send_events: false,
        message_encode_params: {
            address,
            // Define contract ABI in the Application
            // See more info about ABI type here:
            // https://github.com/tonlabs/ever-sdk/blob/master/docs/reference/types-and-methods/mod_abi.md#abi
            abi: {
                type: 'Contract',
                value: HelloWallet.abi,
            },
            call_set: {
                function_name: 'sendValue',
                input: {
                    dest,
                    amount,
                    bounce: false,
                },
            },
            signer: signerKeys(keys),
        },
    };
    console.log(`Sending ${amount} tokens to ${dest}`);
    // Call `sendValue` function
    const response = await client.processing.process_message(sendValueParams);
    console.log('Success. Target account will recieve: %d tokens\n', response.fees.total_output);
    return response.transaction.lt;
}

AppKit API Implementation

async function main(client) {
    // Generate an ed25519 key pair for new account
    const keys = await TonClient.default.crypto.generate_random_sign_keys();

    const helloAcc = new Account(HelloWallet, {
        signer: signerKeys(keys),
        client,
    });

    const address = await helloAcc.getAddress();
    console.log(`Future address of the contract will be: ${address}`);

    // Request contract deployment funds form a local Evernode SE giver
    // not suitable for other networks.
    // Deploy `hello` contract.
    await helloAcc.deploy({ useGiver: true });
    console.log(`Hello contract was deployed at address: ${address}`);

    // Call `touch` function on-chain
    // On-chain execution can be done with `run` function. 
    let response = await helloAcc.run("touch", {});
    console.log(`touch execution transaction is  ${response.transaction.id}`);

    // Read local variable `timestamp` with a get method `getTimestamp`
    // This can be done with `runLocal` function. The execution of runLocal is performed off-chain and does not 
    // cost any gas.
    response = await helloAcc.runLocal("getTimestamp", {});
    console.log("getTimestamp value:", response.decoded.output)

    // Send some money to the random address
    const randomAddress = 
        "0:" + 
        Buffer.from((await client.crypto.generate_random_bytes({length: 32})).bytes, "base64").toString("hex");
    response = await helloAcc.run("sendValue", {
        dest: randomAddress,
        amount: 100_000_000, // 0.1 token
        bounce: true, // delivery will fail and money will be returned back because the random account does not exist.
    });
    console.log(`The tokens were sent, but soon they will come back because bounce = true and destination address does not exist`);
}

(async () => {
    const client = new TonClient({
        network: {
            // Local Evernode-SE instance URL here
            endpoints: ["http://localhost"]
        }
    });
    try {
        console.log("Hello localhost!");
        await main(client);
        process.exit(0);
    } catch (error) {
        if (error.code === 504) {
            console.error(`Network is inaccessible. You have to start Evernode SE using \`everdev se start\`.\n If you run SE on another port or ip, replace http://localhost endpoint with http://localhost:port or http://ip:port in index.js file.`);
        } else {
            console.error(error);
        }
    }
    client.close();
})();

Run it!

Core API

Run:

$ node core

You will see the result of core.js file execution. Core.js file demonstrades core ever-sdk api. It is the same for all ever-sdk bindings.

node core
Future address of Hello wallet contract is: 0:1863addf562c5ab98f3761787458e47406675379a4dc6eb36042ba84bde5cb8d
Transfering 1000000000 tokens from giver to 0:1863addf562c5ab98f3761787458e47406675379a4dc6eb36042ba84bde5cb8d
Success. Tokens were transfered

Deploying Hello wallet contract
Success. Contract was deployed

Hello wallet balance is 986483999
Run `getTimestamp` get method
`timestamp` value is {
  value0: '0x000000000000000000000000000000000000000000000000000000006373fbb4'
}
Calling touch function
Success. TransactionId is: 1a34fbfc336ff8212793077c68bff9f49c6c3f270492afa55ca616ef40b22bec

Waiting for account update
Success. Account was updated, it took 0 sec.

Run `getTimestamp` get method
Updated `timestamp` value is {
  value0: '0x000000000000000000000000000000000000000000000000000000006373fbb6'
}
Sending 100000000 tokens to 0:9f98e8de89e19093145afe134017a783daf8bac5dee04b8810c57a348020764c
Success. Target account will recieve: 99000000 tokens

Normal exit

Appkit API

Run:

$ node appkit

You will see the result of appkit.js file execution. Appkit.js demonstrates high level Appkit package.

Hello localhost!
Future address of the contract will be: 0:5aab70b197897e47ee65faca0ebe24244fd1373d31de2ae39aca28029e0f3469
Hello contract was deployed at address: 0:5aab70b197897e47ee65faca0ebe24244fd1373d31de2ae39aca28029e0f3469
touch execution transaction is  495d0b02905ac541b54407283e52155fbfcbcc804a82ca40d5da96e433fe2f6b
getTimestamp value: {
  value0: '0x000000000000000000000000000000000000000000000000000000006373fa68'
}
The tokens were sent, but soon they will come back because bounce = true and destination address does not exist

Source code

You can find full source code of this sample here

https://github.com/tonlabs/sdk-samples/tree/master/demo/hello-wallet