Generate hash of text file contents Nodejs for checksum

getHash.js

const crypto = require('crypto')
const { readFileSync } = require('fs')

const getHash = (fileBuffer) => {
    const hashSum = crypto.createHash('sha256')
    hashSum.update(fileBuffer)
    const hex = hashSum.digest('hex')
    return hex
}

let file = readFileSync(`file.txt`)
getHash(file)