Calling a Contracts Transition

Review the Javascript that defines callContract.js

Calling a Transition

In the below snippet, we begin to define an async function that will call our public transition for pushing the button. We now define a call to the previously defined contract transition with any associated vnames parameters. The below example shows a call to the HelloWorld contract's transition setHello.

Our example transition name is PressTheButton that takes no additional vnames so we can omit the collection of vnames.

// Calls the previously deployed contract transitionasync function PressTheButton(bech_32_bystr) {  try {    const balance = await zilliqa.blockchain.getBalance(address_from_pk);    const minGasPrice = await zilliqa.blockchain.getMinimumGasPrice();    const myGasPrice = units.toQa('2000', units.Units.Li);     const isGasSufficient = myGasPrice.gte(new BN(minGasPrice.result));     const deployedContract = zilliqa.contracts.at(bech_32_bystr,);
    console.log(`Pressing the button...`);    const callTx = await deployedContract.callWithoutConfirm(        'PressTheButton', // transition name        [],               // no params required        {        version: VERSION,        amount: new BN(0),         gasPrice: myGasPrice,         gasLimit: Long.fromNumber(8000),         },        false,    );
    console.log(`Waiting transaction be confirmed`);    const confirmedTxn = await callTx.confirm(callTx.id);
    //console.log(`The transaction status is:`);    //console.log(confirmedTxn.receipt);    if (confirmedTxn.receipt.success === true)     {      console.log(`Button pressed by : ${address_from_pk}`);    }  }   catch (err)   {    console.log(err);  }}

We then add this call method to our start point to then call the transition from the newly deployed contract. Using Promise.all we can ensure that PressTheButton processes after DeployButtonContract so we have the deployed_contract_base_16 variable defined.

// Application Definition// DEPLOY a contract, // SEND a transaction// LISTEN to events emitted// MONITOR mutable state async function DeploySendListenMonitor(){    deployed_contract_base_16 = await DeployButtonContract();    bech_32_bystr = toBech32Address(deployed_contract_base_16);    console.log(`got ${bech_32_bystr} from ${deployed_contract_base_16}`)
    await Promise.all([        PressTheButton(bech_32_bystr)    ]);}

The console, after waiting for the async call to be returned should reply with. If we examined the contract state, our counter would have increased since we had a successful transaction with no errors thrown.

...Pressing the button...Waiting transaction be confirmedButton pressed by : 0x428A2aA43456FE7fd2De66E48C1fBf372eC10eAE