Contracts¶

There are two types of methods that can be called on a Contract:

A call method may not add, remove or change any data in the storage. These methods are free to call.

A send method requires a fee, but may change the state of the blockchain or any data in the storage. These methods must be made by a transaction and mined before any changes to the state are made. Therefore, these methods are subject to fluctuating gas prices, network congestion, and miner heuristics.

import Contract from '@browseth/contract';

Creating Instances¶

new ^Contract ( ethRef, contractAbi [, options] )

Options may have the properties:

bin — contract binary (required for contract deployment)
address — address of already deployed contract - .send() and .call() will default to this for the {to: address} option

Deploying Contracts¶

^prototype . construct ( [params] )

Takes in constructor parameters for the deploying contract returns send() and gas() methods

. send ( [options] )

deploys contract and returns promise resolving transaction hash

. gas ( [options] )

returns the estimated gas for deploying the contract

Options may have the properties:

chainId — set contract binary for contract deployment
gasPrice — set gas price in wei for transaction
gas — sets the max amount of gas for the transaction

import Browseth from '@browseth/browser'
import Contract from '@browseth/contract'
import PrivateKeySigner from '@browseth/signer-private-key'

const beth = new Browseth(eth_rpc);
beth.useSignerAccount(new PrivateKeySigner(PRIVATE_KEY));

const contractInstance = new Contract(beth, contract.abi, {bin: contract.bin});
const txHash = await contractInstance.construct().send({ gasPrice: 10000000000});

Contract Functions¶

^prototype . fn . functionName ( [params] )

Takes in parameters for calling contract function.

returns send() and call() methods.

. send ( [options] )

makes write call to contract function.

returns promise resolving transaction hash.

. call ( [options] )

makes readonly call to contract function

Options may have the properties:

chainId — set contract binary for contract deployment
gasPrice — set gas price in wei for transaction
gas — sets the max amount of gas for the transaction
to — sets the address of where to send call to (defaults to ‘address’ in initialization)

const txHash = testContractInstance.fn
    .setA(0x123123123)
    .send();

Contract Events¶

^prototype . ev . eventName ( [indexed params] )

Optional indexed parameter values that event log must match.

returns logs() and subscribe() methods.

. logs ( fromBlock, toBlock, contractAddress ): Get logs of contract with block range.

fromBlock — blockNumber (defaults to ‘earliest’)
toBlock — blockNumber (defaults to ‘latest’)

. subscribe ( fromBlock, contractAddress )

Subscribe to contract events with callback.

fromBlock — blockNumber (defaults to ‘latest’)

returns .on() method

.on ( callback ): Calls callback function when event occurs.

contractInstance.ev
    .ASet({ a: 0x123123123 })
    .logs('earliest', 'latest', contractAddress)
    .then(console.log)

contractInstance.ev
    .ASet()
    .subscribe('earliest', contractAddress)
    .on(console.log)