moment().duration().years();

npm install moment

const moment = require('moment'); 
  
let durationOne = moment.duration(250, 'days'); 
let durationTwo = moment.duration(500, 'days'); 
  
// This returns 0 as the duration would 
// not even be a complete year 
console.log( 
  "durationOne years is:", durationOne.years() 
) 
  
// This returns 1 as the duration would be 
// more than 1 year, but less than 2 years 
console.log( 
  "durationTwo years is:", durationTwo.years() 
)

durationOne years is: 0
durationTwo years is: 1

const moment = require('moment'); 
  
let durationA = moment.duration(65, 'weeks'); 
let durationB = moment.duration(256, 'weeks'); 
  
// The asYears() method will return a value 
// of the actual number of years of the duration 
console.log( 
  "Length of durationA in years is:", 
  durationA.asYears() 
) 
  
// The years() method will return the year 
// of the duration 
console.log("durationA years is:", durationA.years() 
) 
  
console.log( 
  "Length of durationB in years is:", durationB.asYears() 
) 
console.log("durationB years is:", durationB.years())

Length of durationA in years is: 1.2457476881797709
durationA years is: 1
Length of durationB in years is: 4.906329356523406
durationB years is: 4