Jenkins, update file contents based off parameter input

Question

I have a build that I want to update the contents of a json based on a parameter input.

I want to update: "version": "1.4.0", to whatever I put in the parameter input as releases frequently skip numbers.

I tried using execute Nodejs script, based on a guide I found. But the variable from the parameter doesn't seem to be readable.

''' const fs = require('fs');

const path = require('path');

let rawdata = fs.readFileSync(path.resolve(__dirname, '/opt/program/package.json'));

let version = JSON.parse('$version'); '''

I get a ReferenceError: $version is not defined

When I run execute shell, for example: echo '$version'

I get the output of the entered parameter.

Is there a way to update part of a json with a shell script?

Is there a better way to use execute NodeJS script?