Setting up Coding Environment

Go into the directory that has the project

npm init

Accepts all defaults Install javascript libraries needed for this projects

npm install web3@0.20.0 solc@0.4.18

Compile Code

Start Ganache Go the the root of your project Start a node console

node
Web3 = require('web3')
web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:7545"))
//last line creates a new web3 object and connect it to the local ganache node
web3.eth.accounts // this will now list he 10 accounts on ganache

Load source and compile it load library from npm dependencies

solc = require('solc')
sourceCode = fs.readFileSync('greetings.sol').toString()

// this loads the source code into a string

Now we compile it

compileCode = solc.compile(sourceCode)

Get the ABI interface

contractABI = JSON.parse(compiledCode.contracts[':Greetings'].interface)
// The greetings is one in the constructor, thats why its upper case

steps to Deploy contract to Ethereum Node

greetingsContract = web3.eth.contract(contractABI)

extract bytecode

byteCode = compileCode.contracts[':Greetings'].bytecode

Deploy Contract

greetingsDeployed = greetingsContract.new({data:byteCode, from: web3.eth.accounts[0],gas: 4700000})

Create an instance of the contract

greetingsInstance = greetingsContrace.at(greetingsDeployed.address)

now we can interact with the contract

greetingsInstance.getGreetings()
greetingsInstance.setGreetings("hello", {from: web3.eth.accounts[0]})

Exit NPM NODE

.exit