Getting 'undefined' trying to read from command line

I'm trying to write code that takes in a number from the command line 'npm run flips --number=10'. I am trying to use minimst to read in the number, 10. I ran 'import minimist from 'minimist' and also tried the following, which yields the same issue.
//import { createRequire } from 'module';
//const require = createRequire(import.meta.url);
//const args = require('minimist')(process.argv.slice(2))

I am using the following to read in the number:
let args = minimist(process.argv.slice(2));

let theNum = args['number'];

console.log(theNum);
//just printing the number to see if i can read it in correctly.

When I run 'npm run flips --number=10', the terminal prints 'undefined' in the console instead of the number.