npm package discovery and stats viewer.

Discover Tips

  • General search

    [free text search, go nuts!]

  • Package details

    pkg:[package-name]

  • User packages

    @[username]

Sponsor

Optimize Toolset

I’ve always been into building performant and accessible sites, but lately I’ve been taking it extremely seriously. So much so that I’ve been building a tool to help me optimize and monitor the sites that I build to make sure that I’m making an attempt to offer the best experience to those who visit them. If you’re into performant, accessible and SEO friendly sites, you might like it too! You can check it out at Optimize Toolset.

About

Hi, 👋, I’m Ryan Hefner  and I built this site for me, and you! The goal of this site was to provide an easy way for me to check the stats on my npm packages, both for prioritizing issues and updates, and to give me a little kick in the pants to keep up on stuff.

As I was building it, I realized that I was actually using the tool to build the tool, and figured I might as well put this out there and hopefully others will find it to be a fast and useful way to search and browse npm packages as I have.

If you’re interested in other things I’m working on, follow me on Twitter or check out the open source projects I’ve been publishing on GitHub.

I am also working on a Twitter bot for this site to tweet the most popular, newest, random packages from npm. Please follow that account now and it will start sending out packages soon–ish.

Open Software & Tools

This site wouldn’t be possible without the immense generosity and tireless efforts from the people who make contributions to the world and share their work via open source initiatives. Thank you 🙏

© 2024 – Pkg Stats / Ryan Hefner

degenerator

v5.0.1

Published

Compiles sync functions into async generator functions

Downloads

36,778,772

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:

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

Gets compiled into:

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:

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 asyncronous function, implement the async get() function, and finally evaluate it into a real JavaScript function instance with the vm module:

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.

License

(The MIT License)

Copyright (c) 2013 Nathan Rajlich <[email protected]>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.