# degenerator

> Compiles sync functions into async generator functions

Latest version **7.0.1** (published 2026-04-06) · MIT license · 0 weekly downloads

## Install

```sh
npm install degenerator
pnpm add degenerator
yarn add degenerator
bun add degenerator
```

## Health

**Score 60/100 (C)** — status: active.

Positive: esm support; no vulnerabilities; has provenance; high maintenance score.

Warnings: low downloads; no types.

## Facts

| | |
|---|---|
| Version | 7.0.1 |
| Published | 2026-04-06 |
| First published | 2013-12-06 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | none |
| Module format | ESM |
| Node | >= 20 |
| Dependencies | 3 |
| Unpacked size | 27.1 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| Provenance | attested (GitHub Actions) |
| GitHub stars | 1165 |
| Author | Nathan Rajlich |
| Maintainers | tootallnate |

## Links

- npm: https://www.npmjs.com/package/degenerator
- Repository: https://github.com/TooTallNate/proxy-agents
- Homepage: https://github.com/TooTallNate/proxy-agents#readme
- Issues: https://github.com/TooTallNate/proxy-agents/issues
- npm.io page: https://npm.io/package/degenerator

## Dependencies (3)

- [esprima](https://npm.io/package/esprima.md) ^4.0.1
- [ast-types](https://npm.io/package/ast-types.md) ^0.13.4
- [escodegen](https://npm.io/package/escodegen.md) ^2.1.0

## Recent versions

- 7.0.1 (latest) — 2026-04-06
- 7.0.0 — 2026-04-01
- 6.0.0 — 2026-03-11
- 5.0.1 — 2023-07-19
- 5.0.0 — 2023-07-18
- 4.0.4 — 2023-06-29
- 4.0.3 — 2023-06-17
- 4.0.2 — 2023-05-09
- 4.0.1 — 2023-05-05
- 4.0.0 — 2023-05-04
- 3.0.4 — 2023-04-23
- 3.0.3 — 2023-04-03
- 3.0.2 — 2022-02-17
- 3.0.1 — 2021-07-12
- 3.0.0 — 2021-07-12
- … 16 more at https://npm.io/package/degenerator/versions

## README

degenerator
===========
### Compiles sync functions into async functions

Sometimes you need to write sync looking code that's really async under the hood.
This module takes a String to one or more synchronous JavaScript functions, and
returns a new String that with those JS functions transpiled into `async`
functions.

So this:

```js
function foo() {
  return a('bar') || b();
}
```

Gets compiled into:

```js
async function foo() {
    return await a('bar') || await b();
}
```

With the compiled output code, you can evaluate the code using the `vm` module
in Node.js, or save the code to a file and require it, or whatever.

Example
-------

You must explicitly specify the names of the functions that should be
"asyncified". So say we wanted to expose a `get(url)` function that did
and HTTP request and returned the response body.

The user has provided us with this implementation:

``` js
function myFn() {
  const one = get('https://google.com');
  const two = get('http://nodejs.org');
  const three = JSON.parse(get('http://jsonip.org'));
  return [one, two, three];
}
```

Now we can compile this into an asynchronous function, implement the
async `get()` function, and finally evaluate it into a real JavaScript function
instance with the `vm` module:


```typescript
import vm from 'vm';
import { degenerator } from 'degenerator';

// The `get()` function is Promise-based (error handling omitted for brevity)
function get(endpoint: string) {
  return new Promise((resolve, reject) => {
    var mod = 0 == endpoint.indexOf('https:') ? require('https') : require('http');
    var req = mod.get(endpoint);
    req.on('response', function (res) {
      var data = '';
      res.setEncoding('utf8');
      res.on('data', function (b) { data += b; });
      res.on('end', function () {
        resolve(data);
      });
    });
  });
}

// Convert the JavaScript string provided from the user (assumed to be `str` var)
str = degenerator(str, [ 'get' ]);

// Turn the JS String into a real async function instance
const asyncFn = vm.runInNewContext(`(${str})`, { get });

// Now we can invoke the function asynchronously
asyncFn().then((res) => {
  // Do something with `res`...
});
```


API
---

### degenerator(code: string, names: Array<string|RegExp>): String

Returns a "degeneratorified" JavaScript string, with `async`/`await` transplanted.

---
_Source: https://npm.io/package/degenerator · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._