TypeScript - DOM & Node lib types

DOM types

document.querySelector('#submit')?.disabled = false;

Node types

import { readFile } from 'fs/promises';

async function main() {
  const text = await readFile('README.md', 'utf8');
  console.log(text);
}

Configuring libs

{
  "compilerOptions": {
    "lib": ["ES2020", "DOM"],
    "types": ["node"]
  }
}

Use types to include ambient type packages (e.g., @types/node). Avoid mixing DOM and Node in the same target unless you truly need both.