const Web3 = require('web3')
const web3 = new Web3('https://mainnet.infura.io/v3/YOUR_INFURA_API_KEY') // YOUR_INFURA_API_KEY替换为你自己的key
// 访问underscore JS库
const _ = web3.utils._
_.each({ key1: 'value1', key2: 'value2' }, (value, key) => {
  console.log(key)
})

  

$ node app

  

key1
key2