Error: Cannot find module 'js-sha256' when running ts script with dfinity HTTPAgent

My code looks like:

import { Actor, HttpAgent } from "@dfinity/agent";
const canisterId = "rrkah-fqaaa-aaaaa-aaaaq-cai";
const host = "http://localhost:8000/";
const agent = new HttpAgent({ host });

However running the script like ts-node script.ts gives me the error:

Error: Cannot find module 'js-sha256'

What am I doing wrong?