const Web3 = require('web3');
// use the given Provider, e.g in Mist, or instantiate a new websocket provider
const web3 = new Web3(Web3.givenProvider || 'ws://localhost:8546');
const web3 = new Web3(Web3.givenProvider || new Web3.providers.WebsocketProvider('ws://localhost:8546'));
// Using the IPC provider in node.js
const net = require('net');
const web3 = new Web3('/Users/myuser/Library/Ethereum/geth.ipc', net); // mac os path
const web3 = new Web3(new Web3.providers.IpcProvider('/Users/myuser/Library/Ethereum/geth.ipc', net)); // mac os path
// on windows the path is: '\\\\.\\pipe\\geth.ipc'
// on linux the path is: '/users/myuser/.ethereum/geth.ipc'