# Is readline-sync ESM-only? Can you require() it?

> readline-sync@1.4.10 is a CommonJS package. CommonJS — require() works on every Node.js version we test.

Synchronous Readline for interactively running to have a conversation with the user via a console(TTY).

Last verified Sep 9, 2026 against readline-sync@1.4.10.

readline-sync ships CommonJS only. require("readline-sync") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >= 0.8.0. import "readline-sync" also works because Node.js and Bun can import CommonJS from ES modules, but only the default export is guaranteed; named imports depend on Node's static analysis of the module.

## What to do

1. require("readline-sync") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >= 0.8.0.
2. From ES modules use the default import: import readlineSync from "readline-sync"; then destructure. Named imports only work when Node.js can statically detect the exports.
3. TypeScript: npm install -D @types/readline-sync

## Facts

- Latest: 1.4.10 (Jul 27, 2019)
- Module format: CommonJS
- Last CommonJS version: 1.4.10
- TypeScript types: @types/readline-sync
- Node engines: >= 0.8.0
- Weekly downloads: 3.1M
- License: MIT

## Runtime test results for readline-sync@1.4.10

Installed and executed on Sep 9, 2026 with require("readline-sync") from a CommonJS file and import "readline-sync" from an ES module.

| Runtime | require("readline-sync") | import "readline-sync" |
|---|---|---|
| Node.js 18 | works | works |
| Node.js 20 | works | works |
| Node.js 22 | works | works |
| Node.js 24 | works | works |
| Node.js 26 | works | works |
| Bun 1.4.0 | works | works |

## How to import readline-sync

ES modules:

```js
import readlineSync from "readline-sync";
```

CommonJS:

```js
const readlineSync = require("readline-sync");
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (65 versions; the newest 60 shown).

| Versions | Format | First published |
|---|---|---|
| 0.2.4 – 1.4.10 | CommonJS | Jun 28, 2014 |

## Frequently asked

**Is readline-sync ESM-only?**

readline-sync@1.4.10 is a CommonJS package. readline-sync ships CommonJS only. require("readline-sync") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >= 0.8.0. import "readline-sync" also works because Node.js and Bun can import CommonJS from ES modules, but only the default export is guaranteed; named imports depend on Node's static analysis of the module.

**Can I import readline-sync with ES module syntax?**

Yes. import readlineSync from "readline-sync" works in Node.js and Bun because they support importing CommonJS modules. Named imports work only when Node.js can statically detect the exports.

**Does readline-sync work in Bun?**

Yes. import "readline-sync" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does readline-sync ship TypeScript types?**

Not bundled. Install the community types with "npm install -D @types/readline-sync".

## Links

- [readline-sync on npm](https://www.npmjs.com/package/readline-sync)
- [Source repository](https://github.com/anseki/readline-sync)
- [HTML version](https://canirequire.com/package/readline-sync/)
- [JSON version](https://canirequire.com/package/readline-sync.json)

---

For scripts and AI agents: any package is at https://canirequire.com/package/<name>/index.md (Markdown) or https://canirequire.com/package/<name>.json (JSON); the site index is https://canirequire.com/llms.txt. Fetch the URL directly; no search needed.