TypeScript setup

esrun does not execute TypeScript natively, nor does it inject ambient globals like Bun or process. But you can get full editor autocompletion and type checking for the runtime:* modules in one command.

One-command setup

esrun types --install writes the bundled definitions into node_modules/@opentf/esrun (as a type package, so your project tree stays clean) and wires them into your tsconfig.json — creating one if you don't have it, or merging into an existing one without touching your other settings.

esrun types --install

What it configures

The types are registered through typeRoots + types — the form editors and language servers load globally, so the runtime:* modules resolve everywhere, not just per-file:

{
  "compilerOptions": {
    "target": "ESNext",
    "module": "ESNext",
    "moduleResolution": "bundler",
    "strict": true,
    "typeRoots": ["node_modules/@types", "node_modules/@opentf"],
    "types": ["esrun"]
  },
  "include": ["**/*.ts"]
}

Use it

Your editor now provides intellisense, inline docs, and type checking for every built-in module:

import { file } from "runtime:fs";

// Your IDE knows `text()` returns a Promise<string>
const data = await file("./config.json").text();