With change-weight you can calculate the equivalent weight in pounds or kilograms using a simple execution of a Javascript function.
npm install change-weight.js
import cw from 'change-weight.js'
// Kilograms to pounds
cw(3, {lb: true}) // 6.61 lb
// Pounds to Kilograms
cw(3, {kg: true}) // 1.36 kg
It's that easy!